Review on recent advances of carbon based adsorbent for methylene blue removal from waste water

Materials Today Chemistry 16 (2020) 100233

Contents lists available at ScienceDirect

Materials Today Chemistry journal homepage: www.journals.elsevier.com/materials-today-chemistry/

Review on recent advances of carbon based adsorbent for methylene blue removal from waste water E. Santoso a, R. Ediati a, *, Y. Kusumawati a, H. Bahruji b, D.O. Sulistiono a, D. Prasetyoko a a

Department of Chemistry, Faculty of Science, Institut Teknologi Sepuluh Nopember, Jl. Arif Rahman Hakim, Kampus ITS Keputih-Sukolilo, Surabaya, 60111, Indonesia b Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Jl. Tungku Link BE1410, Brunei Darussalam

a r t i c l e i n f o

a b s t r a c t

Article history: Received 11 September 2019 Received in revised form 29 November 2019 Accepted 2 December 2019 Available online xxx

The growth in textile and printing industries proven detrimental to the aquatic environment as the industrial waste containing dye seeped into the ecosystem. A high concentration of dye in water possess negative impacts on water ecosystem and harmful to human health. Removal of methylene blue (MB) dye from industrial waste via adsorption pathway has been widely investigated that promised high efficiency of MB removal. This review will summarize researches published from 2008 to 2019 on the removal of MB using carbon adsorbent with focus will be given on the synthesis and modification of carbon-based materials, and the structural properties influencing the performance of MB adsorption. Summary on the type of material used for the synthesis of carbon materials (activated carbon and biochar) will be included from utilization of the naturally occurring carbon sources such as polymers, biomasses and biowastes, and also sucrose and hydrocarbon gases. Modification of carbon materials such as chemical activation and physical activation; surface grafting to form functionalized surfaces; deposition with metal and magnetic nanoparticles via impregnation; and manufacturing of carbon composites will be discussed on the effects to promote MB adsorption and desorption. Another type of carbon adsorbents such as porous carbon; graphitic carbons including graphite, graphene, graphene oxide, and carbon nitride (g-C3N4); and finally nanocarbon in the form of nanotube, nanorod and nanofiber; will be included in the review with details on the synthesis method and the correlation between structural properties and adsorption activity. The regeneration process to increase the life cycle of carbon adsorbent will also be discussed based on two regeneration pathway i.e. a thermal degradation and desorption on MB. Finally the thermodynamics, kinetics, and the adsorption models of MB on carbon adsorbent will be discussed in this review. © 2019 Elsevier Ltd. All rights reserved.

Keywords: Carbon Biochar Graphite Graphene oxide Adsorption Removal Methylene blue

1. Introduction In recent information, more than 100 thousand commercially dye products have discharged to the aquatic environment [1,2]. Textile industries were the largest contributor to water pollution followed by paint, paper, leather, and printing industries [3,4]. Disposal of dye into environment is harmful to the aquatic life ecosystem, and posed negative impact to human health. The consequences can be in the form of aesthetic disorders, such as discoloration and foul-smelling water and life disruption of water ecosystems due to reduction of sunlight penetration and depletion

* Corresponding author. E-mail addresses: [email protected], [email protected] (R. Ediati). https://doi.org/10.1016/j.mtchem.2019.100233 2468-5194/© 2019 Elsevier Ltd. All rights reserved.

of oxygen level in water. The risk of dye pollution in water for human health includes the emergence of skin diseases upon contact with polluted water and digestive disorders from water consumption that may lead to the potential risk of cancer [5,6]. MB is used in industries for coloring paper, cotton, silk, wool and for hair coloring and reported to cause several risks to human health, such as eye, respiratory, digestive and mental disorders [7,8]. Removal of MB from industrial waste has been investigated using various methods such as enzymatic process, photodegradation reaction, electrochemical removal, chemical coagulation, membrane filtration and physical adsorption methods [8]. Fig. 1 illustrates the trend on researches published from 2008 to 2018 on the removal of MB from water. The adsorption is among the most investigated methods for MB removal with the number of publications showed more than twofold increment within 10 years.

2

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

Fig. 1. The plot of number of publications based on methods employed for the removal of methylene blue from water published since 2008 until 2018 (Data source, Sciencedirect.com).

The adsorption method followed a simple procedure with utilization of low cost and abundant adsorbent, and also able to maintain high efficiency of MB removal. The adsorption process also prevents the formation of secondary pollutants that can occur through oxidation or degradation of MB [4,9]. The development on carbon-based adsorbent for MB removal have received significant interests since the past 10 years and therefore, this review will only be limited on the study of carbon adsorbent for MB removal based on the researches published between 2008 until 2019. Carbon adsorbent will be divided into six groups as summarized in Table 1 and the percentage is tabulated in Fig. 2. The activated carbon synthesized from naturally occurring carbon sources such as biomass, biomass waste, and industrial waste is the most investigated group or carbon due to the availability of raw materials and the simple method of production. Second type of carbon is the modified activated carbon using clay, metal and metal oxide nanoparticles. Biochar is type of carbon produced using biomass that has been investigated carbon adsorbent. Graphitic carbon and its derivatives resulting from modification of graphite and g-C3N4 is the fourth most investigated carbon as adsorbent for MB. Fifth, porous carbon produced from commercially available carbon sources with template or pore directing agent. Finally, carbon nanoparticles including carbon nanorods, nanotubes and nanofibers as shown in Fig. 3. 2. Structural properties of carbon and correlation with the adsorption capacity The benchmark for classification of carbon material as excellent or poor adsorbent relies on the surface area of and the pore structure of carbon. The properties are crucial to accommodate the

Fig. 2. Research of carbon adsorbents for the removal of methylene blue based on the number of articles available in 2008 until 2019.

adsorbed MB and also to determine the adsorption capacity of carbon [69,126,127]. Apart from the surface area and the pore structure, MB adsorption also influenced by the particle size of carbon, the surface acidity, and the functionality that affected the interaction between MB and carbon [35]. Based on the value of MB adsorption capacity summarized in Table 1, the carbon adsorbent can be divided into four groups; superior adsorbents (with the adsorption capacity more than 1000 mg/g), excellent adsorbent (500e1000 mg/g), moderate adsorbent (100e500 mg/g) and poor adsorbent (less than 100 mg/g). Fig. 2 shows a three dimensional (3D) plot of the surface area and the pore diameter of carbon adsorbent versus the adsorption capacity of MB, that were collected from researches published within 2008e2019. In general, the adsorption capacity of carbon adsorbent showed positive correlation with the surface area. However, the trend is not applicable to all carbon adsorbent, in which some carbon with high surface area showed low adsorption capacity. As the surface area has positive impact in enhancing the adsorption capacity of carbon, increasing the pore diameter of adsorbent does not necessarily improved the adsorption capacity. The pore size above 6 nm seems to show no advantage in increasing the amount of adsorbed MB. However, adsorbent with high surface area but with moderate pore diameter showed high level of MB adsorption capacity with the value exceeding 800 mg/g. The dimensions of MB in water is recorded as 0.400
0.793
1.634 nm, therefore the size of pore opening of adsorbent is crucial as to allow the diffusion of MB within the pores [113]. The correlation between the adsorption capacities of the

Table 1 The structural properties of carbon-based adsorbents for MB removal available from 2008 to 2019. No

Carbon- based adsorbents

SBET (m2/g)

f (nm)

Qm (mg/g)

References

1 2 3 4 5 6

Activated carbon Biochar Modified biochar and modified activated carbon Graphitic carbon and its modification Porous carbon materials Carbon Nanotube materials

4.445e2854 2.05e2054.49 4.02e1229 32e295.56 21e3496 140e558.7

1.0e15.9 2.29e20.57 1.038e7.477 2e50 0.74e5.45 2.19e25

0.71e1030 2.06e1282.6 9.72e986.8 41.67e847 8.96e1791 33.4e1189

[7,10e58] [40,59e74] [75e95] [29,85,88,96e106] [107e117] [29,118e125]

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

3

Fig. 3. Distribution of the adsorption capacity of carbon-based adsorbents for MB with correlation to the pore size and the BET surface area from researches available from 2008 to 2019.

adsorbent versus the pore diameter showed that the highest capacity of 1791 mg/g were observed from carbon with surface area of 2138 m2/g and pore diameter of 3.33 nm [100]. It is interesting to see that carbon with pore diameter larger than 6 nm and surface area of 500 m2/g have lower adsorption capacity with most of the adsorbents showed less than 500 mg/g of MB capacity. 3. The role of surface functional groups on adsorption of methylene blue Apart from the surface area and the porosity of carbon adsorbent, the presence of functional groups such as aromatic ring, eC] O, -C-O-C-, eOH, eNH2, eC]S, eC]N, eS]O on carbon surface also has a vital role in increasing the adsorption capacity for the separation of methylene blue from water [52,62,78,97,106,128]. Methylene blue is a cationic molecule containing 6-carbon aromatic ring, nitrogen, and sulfur in its molecular structures, which influenced the interaction with carbon surface. The adsorption process of methylene blue on carbon occurred via electrostatic interaction, the formation of hydrogen bridge, the electron donoracceptor relationship, and the p-p electron dispersion forces between the functional groups of carbon surfaces with MB molecules [52,120,121]. Thermal activation is a preferred method to increase surface functionality of carbon adsorbent which often conducted by

annealing at high temperatures under the flow of N2. The process improved the number of carboxyl groups (-COOH) and also increased the porosity and the surface area of carbon which consequently enhanced the adsorption capacity of methylene blue [10,22,27,30,43,54,57,59]. Another pathway for promoting surface functionality of carbon is to form composites by chemical activation using chemicals that contained the desired functional groups. ElShafey et al. (2016) have introduced eNH2 groups on carbon surface by treating carbon material from biomass with ethylene diamine, propylene diamine, ethylene amine, and aniline. Zhang and Xu (2014) have encapsulated carbon nanotubes with poly (sodium 4-styrenesulfonate) to graft eSO3 group on the carbon surface [120]. Robati et al. (2016) have attached the eNH and eSH functional groups to the surface through the reaction of cysteamine with carboxylic groups on the nanocarbon surface [122]. Que et al. (2018) have coated eSO3 groups of sodium dodecyl sulfate on the biochar surface to increase methylene blue adsorption capacity [64]. Formation of activated carbon composites such as charcol/ chitosan composites produced carbon with increased number of eC]O, eOH, and eNH2 functional groups and subsequently increased the adsorption capacity of methylene blue [129]. Tong et al. (2018) produced carbon/montmorillonite composites to incorporate SieO and AleOH groups on the surface of carbon material [84].

4

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

4. The carbon-based adsorbents for MB adsorption

Table 3 Surface area, pore diameter, and adsorption capacity of activated carbon (AC) from biomass vetiver roots with different methods of activation [43].

4.1. Activated carbon from biomass and biowastes Biomass and its waste are the most extensive renewable carbon sources investigated for the production of activated carbon, which the source varying from plants to animal waste (Table 12). Fig. 4 provides general steps for the synthesis of activated carbon from biomass. Generally, the synthesis involved three steps of procedures that begin with pretreatment of biomass to remove impurities. The biomass is pretreated via washing and drying to eliminate any contaminants that may affect the purity of the resulting carbon. This preliminary process also included grinding and sieving of the biomass waste to reduce the size for carbon precursor. The second stage is carbonization process that often occurred through annealing at moderate or high temperature under inert atmosphere. The final stage is the activation process to enhance surface functionality of carbon. The carbonization and activation steps can also occur simultaneously as presented in Fig. 5. Table 2 summarized the properties of activated carbon produced from different type of biomasses while using various chemical activators for MB adsorption. For the synthesis of activated carbon from date press cake (DPC) biomass, the process occurred via two steps of reactions which were the conversion of dried DPC into carbonized material (CM) through annealing followed by the activation process with KOH. The mixtures of carbonized material and KOH were heated at 750  C for 90 min under the flow of nitrogen [51]. Danish et al. (2018) stated that the types of chemical and gas used during activation process significantly influenced the formation of pore structure, the surface area, the functionality and therefore affected the adsorption capacity of activated carbon [50]. Activated carbon produced from Citrus pectin with using ZnCl2 as activator has the surface area and the capacity adsorption of 1983 m2/g and 1155.2 mg/g, respectively. Meanwhile the production of activated carbon using cotton stalk with ZnCl2 activator produced 794.84 m2/g with 315.45 mg/g of MB capacity. The researches implied the sources of biomass also influenced the structural properties and the adsorption capacity of activated carbon. Altenor et al. [11] produced activated carbon from vetiver roots with using H3PO4 and steam as activators (Table 3). The studies revealed that introducing H3PO4 improved the pore size of activated carbon and significantly enhanced the adsorption of MB. Liu et al. [15] produced activated carbon from bamboo blue using H3PO4 activators via microwave radiation (Table 4). The resulting activated carbon have high surface area with approximately 1300e1400 m2/g. Increasing the duration of microwave treatment

Properties of AC

Activator: steam

Activator: H3PO4 85%, The ratio of activator/biomass: 0.5 (w/w)

1.0 (w/w)

1.5 (w/w)

SBET (m2/g) fpore (nm) Qm (mg/g)

1185 2.16 375

1170 2.04 381

1272 2.83 394

1004 3.04 423

Note: Q m is the adsorption capacity of activated carbon for MB.

enhanced the pore size and subsequently improved adsorption capacity. Establishing the correlation between the surface area, the pore size, and the adsorption capacity of activated carbon is a challenging task, as there are different other factors that also contributed to the efficiency of the adsorption process. For example Karagoz et al. (2008) emphasized that the MB adsorption on activated carbon was affected by the electrostatic interactions between the adsorbents and the adsorbates so that various surface functional groups such as phenolic, lactonic and carboxylic groups affected the surface acidity of carbon [10]. The effect of surface acidity on the efficiency of MB adsorption were also confirmed by others [22,27,30,43,54,57,59]. Meanwhile Sheikha S. Ashour (2010) suggested that both acidity and surface alkalinity have significant effects on the adsorption capacity of activated carbon for MB adsorption. Activated carbon resulting from chemical activation at 800  C produced acidic surface, meanwhile physical activation by annealing at 900e1000  C produced activated carbon with surface alkalinity [56]. The observation was supported by Reffas et al. that showed the adsorption of MB on the surface of activated carbon was dictated by the presence of p-p interaction between the basic sites of carbon surface with MB molecules [55]. Benadjemia et al. (2011) also reported the influence of carbon pore structure on the adsorption of MB. The studies indicated that MB molecules were unable to penetrate pores with the size less than 1.0 nm (supermicropore). However, activated carbon with micropore structure with minimum diameter of 1.33 nm showed high capacity of MB adsorption in comparison to activated carbon with mesomacropore struture [14]. Vargas et al. (2011) presented four possible models of interaction between MB and activated carbon, which were the electrostatic interaction, the hydrogen bridge formation, the electron donor-acceptor relationship, and the p-p electron dispersion forces [52]. However, Heidarinejad et al. (2018) believed that the

Table 2 Source of biomass, chemical activator and structural properties of activated carbon or biochar and adsorption capacity for MB. Biomass

Activator

Activated carbon or Activated biochar properties

Cotton stalk Flamboyant pods (D. regia) Waste tea Oil palm fiber Empty fruit bunches Orange peels Mangosteen peels Citrus pectin Fish scales (Labeo rohita) Coconut shell Date Press Cake Municipal solid wastesa) Weedsa) a

Activated biochar.

ZnCl2 NaOH CH3COOK KOH KOH K2CO3 K2CO3 ZnCl2 NaOH NaOH KOH KOH HNO3

References

SBET(m /g)

fpore (nm)

Qm (mg/g)

794.84 2854 854.30 1223 1372 543.89 485.89 1983 1867 876.14 2632.5 662.4 5.138

3.20 2.24 2.42 2.357 2.206 2.258 2.304 <2 2.5 2.86 1.9044 >2 >2

315.45 890 554.30 379.62 395.30 243.66 277.45 1155.2 184.40 200.01 546.8 21.83 92.59

2

[54] [52] [13] [22] [22] [53] [53] [69] [71] [45] [51] [63] [65]

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

5

Table 4 The structural properties of activated carbon from bamboo obtained using different time intervals of microwave radiation [57]. Activated carbon

Time interval (min)

SBET (m2/g)

Pore size (nm)

Qm,

AC-1 AC-2 AC-3 AC-4

No radiation 2 5 10

1335 1409 1357 1323

1.87 1.90 2.02 2.11

195.8 327.3 472.8 618.5

LF

(mg/g)

Table 5 Physical properties and the adsorption capacity of activated carbon before and after modification. Activated Carbon (AC) sources

Modifier

Before modification

After modification

Ref.

SBET (m /g) fpore (nm) Qm (mg/g) SBET (m /g) fpore (nm) Qm (mg/g) 2

Commercial AC Activated carbons (AC) from date palm leaflet

AC without modifier EDA þ TC þ HNO3 PDA þ TC þ HNO3 EA þ TC þ HNO3 AN þ TC þ HNO3 Activated carbons (AC) from coconut shells Ca Alginate Granular activated carbon (GAC) from spent coffee grounds Ca-Alginate Commercial AC Au Nanoparticles Commercial AC Ag Nanoparticles Commercial AC Pd Nanoparticles Commercial AC ZnS þ Cu Nanoparticles Commercial AC AgCl Nanorods Commercial AC CuS Nanoparticles Commercial AC Chitosan-Fe3O4 The spent bleaching sorbent of olive pomace oil Clay Sucrose Red mud

2

1688 823

2.5 2.27

263.49 270

1620.0 e e e e e e e e e 3.531

1.32 e e e e e e e e e 1e2

1030 e e e e e e e e e e

e 4.02 6.78 9.89 17.7 733.8 704.23 1229 e e e e e 123.84 355.11 105.09

e 15.2 18.6 16.8 11.6 1.038 2.197 4.88 e e e e e e 5.83 1.4e5

e 200 182 393 34.7 892 986.8 185 71.43 75.4 106.9 666.67 208.3 500 178.64 76.92

[29] [78]

[90] [141] [91] [76] [76] [95] [80] [81] [129] [82] [114]

Note: EDA (ethylene diamine), PDA (propylene diamine), EA (ethylene amine), AN (aniline), TC (thionyl chloride).

Table 6 Physical properties and adsorption capacity of graphite and its derivatives as adsorbents and for MB removal. Adsorbent

Expandable graphite Graphite powder Expandable graphite Graphene oxide Graphene oxide Natural graphite powder Graphite Natural graphite powder Graphene Oxide Graphene oxide

Modifier

Hummers' reagent, HNO3 H2SO4, HNO3 Hummers' reagent, hydrazine MWCNT MWCNT, FeCl3, H2SO4, K2S2O8, P2O5, KMnO4, H2O2 H2SO4, KMnO4, NaNO3, H2O2 H2SO4, KMnO4, NaNO3, H2O2 TiO2 MgO

Before modification

After modification

Ref.

SBET (m2/g)

fpore (nm)

Qm (mg/g)

SBET (m2/g)

fpore (nm)

Qm (mg/g)

e e e e e e e e e e

e e e e e e e e e e

e e e e 24.88 e 29.01 e 750 333

32 e 295.56 78.9 e e e e e e

17.3 e 3.49 2 e e e e e e

240.65 0.003 153.85 81.97 65.79 476.19 599.8 467.3 900 833

[29] [100] [101] [102] [103] [104] [105] [106] [96] [97]

Note: MWCNT (multiwall carbon nanotubes).

mechanism of MB adsorption on activated carbon was not entirely controlled by the electrostatic interactions as evidenced by the positive effect of the ionic strength on increasing the adsorption capacity. The changes on the ionic strength usually occurred due to the presence of intermolecular forces between the adsorbate molecules and the compression of diffuse double layer on the surface of the adsorbent [51]. 4.2. Biochar Biochar is another type of carbon based adsorbent derived from pyrolysis of biomass and biomass waste in a limited oxygen environment (Table 12). Biochar also often possesses similar structural properties as activated carbon. Hagemann et al. (2018) described that the activated carbon and biochar are two types of carbonaceous pyrogenic materials that shared similar terminology, fabrication process, and application. Initially, biochar was used in agricultural field, however the application as adsorbent for waste water treatment have received significant attention in recent years

[130]. Angela et al. (2018) synthesized activated biochar and activated biochar and activated carbon from municipal solid waste with micropore volume content of 0%e25%, with the capacity of biochar adsorption, activated biochar, and activated carbon varies greatly, depending on the raw materials and the pyrolysis processes [63]. Sun et al. (2013) have synthesized biochar with pyrolysis temperature of 400  C from anaerobic digestion residues, palm bark, and eucalyptus, with adsorption capacity for methylene blue were observed at 9.77, 2.95, 2.0 mg/g respectively [59]. Ji et al. (2019) produced biochar from a fallen leaf via pyrolysis at 500  C, which resulted carbon with adsorption capacity for methylene blue of 78.6 mg/g [61]. Ahmed et al. (2019) synthesized biochar from pyrolysis of seaweed (Gelidiella acerosa) at 800  C with adsorption capacity for methylene blue ~512.67 mg/g [74]. Que et al. (2018) described that biochar has high specific surface area, porous structure, and a large number of surface functional groups, however the surface area and micro-volume of biochar are still lower than activated carbon. Synthesis of biochar from biomass via pyrolysis generally occurred at relatively lower temperature

6

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

Table 7 Carbon precursor, chemical activator, physical properties and adsorption capacity of porous carbon for MB adsorption. Carbon precursor sources

Activator

Activated carbon properties

Ref.

SBET(m2/g) fpore (nm) Qm (mg/g) Furfuryl alcohol (FA) using acid and alkaline treated zeolite X as the template

HF

764 936 Sucrose with mesoporous silicas as hard template and Pluronic copolymers as pore-creating agents KOH 255 705 KOH, thermal 720 820 700 680 poly(vinyl alcohol) microspheres (PVAms) H2SO4, thermal e Polycondensation of resorcinol (R) and formaldehyde (F) e 651.83 67.22 TiO2 Commercial sucrose e 24.4 Thermal 562.7 KOH, thermal 1534 Sucrose from a local market e 3.531 Red mud 105.090 Glycerol H2SO4, thermal 21 464 Poly(vinyl alcohol) (PVA) with MnO as template H2SO4, thermal 820 2138 180 ZIF-8 Steam, thermal short time 1465 Steam, thermal long time 1694 Thermal only 1049 Chitosan Thermal, KOH 3496

2.8e7.0 2.6e5.5 1.8 4.1 2.3 3.3 2.1 3.6 e 0.74 4.65 4.92 1.86 2.00 <1 1.4e5 3.66 3.65 e e e 1.5 1.5 1.5 2.7

262.87 436.55 38.39 499.04 428.67 415.87 611.01 323.10 484 1.10 15.24 e e 704.2 e 76.923 865 156 1351 2936 1085 97.2 100.2 26.8 890.32

[107] [108] [110]

[111] [112] [113]

[114] [115] [116]

[117]

[109]

Table 8 Properties of carbon nanotubes and their modifications for adsorption of MB. Adsorbent

Modifier

Before modification

Carbon nanotube (CNT) CNT CNT CNT Cup-stacked carbon nanotube (CSCNT) Carboxyl functionalized mul-tiwall carbon nanotubes (MWCNT-COOH) CNT Oxidized multiwalled carbonnanotube (OMWCNT) (MWCNT-COOH)

e e Spherical cellulose, welan gum polysaccharide Poly (sodium 4-styrenesulfonate) KOH Cysteamine Laponite RD K-carrageenan, Fe3O4 Calcium-alginate (CA)

(<700  C) than activated carbon [64]. Table 2 summarized the adsorption capacity of methylene blue and the structural properties of biochar. In general, biochar possess low surface area, with pore diameter less than 2 nm and the adsorption was significantly lower than activated carbon. 4.3. Modified activated carbon/biochar Modified activated carbon is a group of adsorbents resulting from the treatment of activated carbon with inorganic salt solution, organic solvent or metal nanoparticles. The modification aims to increase surface functionality in order to enhance the adsorption capacity and also to facilitate the removal of adsorbed MB. Fig. 6 summarized the methods for modification of activated carbon based on the literatures. In general, modification of carbon materials using base, acid, or salt solutions produced oxidized carbon with enhanced surface acidity or porosity [10]. Reaction between carbon with base solution is described as following equation [90,131]. 2C þ 6NaOH / 2Na þ 2Na2CO3 þ H2

After modification

Ref.

SBET (m / fpore g) (nm)

Qm (mg/ SBET (m / fpore g) g) (nm)

177 e e

12.1 e e

188.68 46.2 e

e e e

e e e

e e 308

[29] [118] [119]

140.4 218.7 e

25.0 2.20 e

45.9 50.5 166.7

164.6 558.7 e

11.5 2.19 e

100 319.1 200

[120] [121] [122]

e 238.7

e e

72 e 33.4

e 169.0

e e

212.75 46.36 1189

[123] [124] [125]

2

2

Qm (mg/ g)

Modification with amine compounds such as ethylene diamine, propylene diamine and aniline produced activated carbon with enhanced amine functionalized surface [78]. Activated carbonbased composites were produced by modification of activated carbon with metal nanoparticles, such as Au, Ag, Cu, and Pd [66,70,74] and also metal oxide such as CuO, NiS, ZnS, CuS, and Fe3O4 [67,68,74,129]. The addition of metal or metal oxide nanoparticles were generally carried out by impregnation method. For example modification with Ag nanorods were carried out by immersion of activated carbon on Ag nanorods suspension in an ultrasonic bath at room temperature [80]. The resulting Ag/activated carbon composites showed enhanced efficiency for MB removal. The modification of carbon materials was also employed using naturally occurring materials such as clay for example AC/clay composite [82], palygorskite/carbon composite [93], carbon/ montmorillonite nanocomposites [84], AC/Ca Alginate/bentonite composite [94], hydrotalcite an anionic clay (MgAl-LDH/Biochar composites [85]. Apart from that, chitosan was also used to form magnetic chitosan/active charcoal composite [129]. Hatice Karaer and Ismet Kaya (2016) examined the addition of chitosan and Fe3O4 in activated carbon that allowed efficient separation of MB without

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

7

Table 9 The values of thermodynamic parameters and the best-fit isotherm of MB adsorption on different type of carbon-based adsorbents. Adsorbent

Isotherm type

Activated carbon fibers (ACFs)

Freundlich

Modified expanded graphite powder

Carbon nanotubes

Activated carbon prepared from Posidonia oceanica (L.) dead leaves

Waste tea activated carbon

Industrial solid waste derived activated carbon prepared by microwave heating

Graphene

Modified ACFs by chemical vapor deposition

Acacia fumosa seed shell activated carbon

Activated carbon derived from Pistacia khinjuk

Activated carbon prepared from dross licorice by ultrasonic Activated carbon (AC) from peanut sticks wood.

Biomass-derived highly porous functional carbon

Activated carbon based coconut shells Calcium alginate beads Calcium alginate/activated carbon composite beads Magnetic graphene-carbon nanotube composite

Activated carbon/Au nanoparticles composite

Activated carbon from lubricating oil and the ground palm stems mixing

Palygorskite/carbon nanocomposite

Porous carbon from tea waste

Pyrolytic tire char

Calcium alginate/bentonite/activated carbon composite beads

Activated carbon spheres from poly(vinyl alcohol) microspheres

Carbon/TiO2 composite

Konjac glucomannan (KGM)-based magnetic carbon aerogels

T (K) DGo (kJ.mol1) DHo (kJ.mol1) DSo (J.mol1.K1) Ref.

294 296 298 Langmuir 293 318 343 Langmuir 273 298 333 Langmuir 298 308 318 Langmuir 303 313 323 Langmuir 303 313 323 Langmuir 293 313 333 Freundlich 308 318 328 Langmuir 303 313 323 Langmuir 293 303 313 Langmuir 293 313 Langmuir-Freundlich 298 308 323 Langmuir 313 323 333 Langmuir 293 313 Langmuir 293 313 Langmuir 293 313 Langmuir 293 303 313 Langmuir 293 303 313 Langmuir 303 313 323 Langmuir 298 308 318 Langmuir 303 313 323 Freundlich 298 308 318 Freundlich 303 313 323 Langmuir 298 308 318 Freundlich 298 313 328 Langmuir 303 313

15.003a 15.821 16.639 64.50b 69.00 69.19 10.9c 11.0 14.8 30.90d 30.37 28.14 7.796e 10.663 10.797 4.95c 1.83 0.28 0.89c 1.80 3.28 30.72c 32.40 33.95 0.29e 0.23 0.17 2.116f 5.534 7.616 2.3e 5.1 6.376a 7.322 8.872 0.356c 0.831 1.305 8.388a 8.172 7.148 5.504 7.758 7.260 5.072d 5.592 6.055 4.643f 5.724 6.313 7.1e 7.7 8.4 6.74f 7.18 7.63 10.81e 13.53 16.25 27.42c 29.35 30.46 5.920a 5.844 5.723 12.46c 13.58 14.20 568.81e 296.48 24.16 31.32c 32.40

105.250

409

[7]

13.17 13.00 12.76 7.29

0.175 0.179 0.164 64.6

[100]

38.96

0.234

[11]

10.871

45.7

[13]

84.40

262.73

[22]

16.54

59.25

[101]

12.52

140.9

[75]

3.66

61.55

[31]

53.83

193.59

[33]

109.6

366.23

[35]

22.794

97.88

[135]

2.95

47.38

[140]

7.656

[90]

8.720

2.5 3.6 15 9.1 7.7 5.6 47.22

[103]

43.216

197.32

[91]

13.04

63.0

[39]

6.51

44.46

[93]

71.62

270

[67]

17.68

152

[40]

8.897

9.802

[94]

13.78

88.24

[111]

5.979

18.155

[112]

25.776

187.6

[79]

2.647 5.505

[118]

(continued on next page)

8

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

Table 9 (continued ) Adsorbent

Isotherm type

KOH-activated carbon from sucrose spherical carbon

Redliche Peterson

Reduced graphene oxide/titania nanocomposite

Langmuir

Citric acid functionalized magnetic graphene oxide coated corn straw

Freundlich

Magnetic chitosan/active charcoal composite

Langmuir

Natural cotton based flexible carbon fiber aerogels

Langmuir

Nitrogen-rich mesoporous carbon from fishery waste

Langmuir

Hydrochar from coffee husks

Langmuir

Microwave assisted corncob activated carbon

Freundlich

Nanoporous activated carbon prepared from karanj (Pongamia pinnata) fruit hulls Langmuir

Activated carbon developed from Ficus carica bast

Langmuir

Glycerol based carbon

Langmuir

Loofah sponge-based porous carbons

Langmuir

a b c d e f g h

K K K K K K K K

¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼

T (K) DGo (kJ.mol1) DHo (kJ.mol1) DSo (J.mol1.K1) Ref. 323 298 308 318 298 308 318 298 318 328 298 308 318 298 308 318 303 313 323 303 313 323 303 313 323 303 313 323 303 313 323 299 304 313 303 318 333

35.08 1.71e 1.97 2.91 22.74c 25.43 27.04 9.25f 7.75 4.74 8.38g 10.44 12.18 10.41h 9.22 8.72 4.638e 6.511 9.429 11.56d 14.75 16.40 12.481a 9.598 8.767 0.269e 2.062 2.841 1.55e

28.70c 30.33 34.49 6.59e 11.22 15.85

16.30

0.060

[113]

180.14

34.25

[96]

42.66

111.37

[142]

48.27

190

[129]

29.44

64.59

[42]

67.77

238.44

[71]

49.79

204.27

[72]

55.737

144.733

[48]

38.885

130

[47]

21.55

76.24

[49]

102.00

440.0

[115]

86.90

308.70

[73]

Kid ¼ Cad,e/Ce (the distribution coefficient), where the value of Kid is obtained from the lowest experimental adsorbate concentration. K* ¼ h.ln k2/kB.T (k2: the second-order kinetic rate constant, h: Planck's constant, kB: Boltzmann's constant). KL (the Langmuir equilibrium constant). Kd ¼ (qe/Ce)r (r ¼ 1000 g/L, the density of the aqueous solution). Ko ¼ qe/Ce (the distribution coefficient). K0 (K0 values were calculated from the relation ln qe/Ce vs. qe at different temperatures and extrapolating to zero). Kc, where Kc (L/g), is the equilibrium constant obtained from the Langmuir constants Qm and KL (Kc ¼ KL.Qm). Kdis ¼ KL.Mr (Mr is the relative molecular weight of MB).

the use of filter paper or other devices, with large adsorption capacity of 500 mg/g [129]. Studies on the formation of AC/red mud composite [114], biochar/iron oxide composite [98] and graphitic carbon Biochar/g-C3N4 composites [88] were carried out with enhanced adsorption capacity of MB. Marrakchi et al. (2017) reported that the addition of clay in carbon and activated carbon produced composite materials with pore diameter of 5.52 nm and 5.83 nm. The MB adsorption capacity of the composites were strongly affected by the pH of the adsorbate solution, which confirms that the adsorption was dictated by electrostatic interactions between the adsorbent and the adsorbate [82]. Kazak et al. (2017) synthesized red mud@carbon composites from sucrose that produced high surface area composites with pore diameter of 1.4e5 nm. The red mud@carbon composite showed ~98% of MB removal efficiency with 5 times reproducibility for adsorption and desorption of MB [114]. Table 5 summarized structural properties of modified activated carbon and adsorption capacity for MB adsorption. Several researches indicated that modification of activated carbon not necessarily guaranteed positive effects on increasing the adsorption capacity of activated carbon [78,90]. However, the modification showed improvement in accelerating the time of equilibrium

adsorption and facilitate the separation process of the adsorbed MB [78,90]. El-Shafey et al. (2016) investigated the effect of EDA (ethylene diamine), PDA (propylene diamine), EA (ethylene amine), AN (aniline), and TC (thionyl chloride) on activated carbon surface. Characterization of the activated carbon following modification showed the increased of activated carbon pore size from 2 nm to 10e20 nm however the surface area of activated carbon reduced 823 m2/g to only ~ 4e18 m2/g. Important observation from the investigation was the effect of treatment on the surface properties of activated carbon. Modification with nitric acid (HNO3) increased the surface acidity meanwhile treatment with EDA and PDA produced activated carbon with high surface basicity. Activated carbon treated with EA and AN enhanced the hydrophobicity of the surface. The results showed that functionalizing the surface of activated carbon with ethylene amine increased the activated carbon adsorption capacity from 270 mg/g to 398 mg/g. The results suggested that the adsorption of MB on activated carbon occurred via various interactions either via hydrogen bonds formation, Van der Waals attraction, electrostatic interaction or hydrophobic forces. However due to high adsorption of MB was observed on activated carbon modified with ethylene amine, the studies suggested that the hydrophobic force formed stronger interaction to retain MB on

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

9

Table 10 Summary of the best-fit parameters of various kinetic models for MB adsorption onto carbon-based adsorbents. Adsorben

Model

T (K)

Rate constant (k)

R2

Ref.

Activated carbons from waste biomass Mesoporous carbons from furfuryl alcohol Activated carbons developed from date pits Activated carbon from bamboo Activated carbon from Egyptian rice hull Activated carbon prepared from Posidonia oceanica (L.) dead leaves Activated carbon from coconut shell Waste tea activated carbon Magnetite loaded multi-wall carbon nanotube Industrial solid waste derived activated carbon Graphene Ag NPs-AC Pd NPs-AC Agricultural wastes-based activated carbons Biochars from palm bark Graphene oxide Graphite oxide nanoparticle Magnetic graphene-carbon nanotube composite Cpper oxide/activated carbon composite Activated carbon from Albizia lebbeck seed pods Spent coal based activated carbon Activated carbon from two waste streams Carbon nanotubes/poly (sodium 4-styrenesulfonate) composite Palygorskite/carbon composite Porous carbon prepared from tea waste Pyrolytic tire char Activated carbon from factory-rejected tea ZnS:Cu NPs/activated carbon Wood millet carbon AC spheres from PVA microspheres Carbon/TiO2 composite Porous carbons from Citrus pectin Konjac glucomannan (KGM)-based magnetic carbon aerogels Activated carbon from sucrose spherical carbon Reduced graphene oxide/titania nanocomposites AgCl nanorods/activated carbon composite CuS nanoparticle/activated carbon composite Graphene oxide/magnesium oxide nanocomposites OMWCNT/carrageenan/Fe3O4 nanocomposites Red mud@sucrose based carbon composite Activated carboneclay composite Activated natural cotton based flexible carbon fiber aerogels Nitrogen-rich mesoporous carbon from fishery waste Carbon from coffee husk Mesoporous activated coconut shell-derived hydrochar Nanoporous activated carbon from karanj (Pongamia pinnata) fruit hull Activated carbon from corncob Activated carbon from Ficus carica bast Glycerol based carbon Porous cellulose derived carbon/montmorillonite nanocomposites An ultra-high surface area mesoporous carbon Heteroatom-doped porous carbon MWCNT/alginate composite Loofah sponge-based porous carbons Chitosan-derived three-dimensional porous carbon

Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Pseudo-2nd-order Intra-particle diffusion Pseudo-2nd-order Pseudo-2nd-order Pseudo-1st-order Intra-particle diffusion Pseudo-2nd-order Pseudo-2nd-order Intra-particle diffusion Pseudo-2nd-order Ritchie Pseudo-2nd-order Pseudo-2nd-order

298 308 300 298 298 298 298 303 298 303 293 298 298 303 313 298 299 283 293 298 298 303 298 298 303 298 303 298 298 298 298 298 303 298 298 298 298 298 298 298 303 298 303 298 303 303 303 303 298 298 298 298 298 298 298

k2 ¼ 0.003141 k2 ¼ 0.00637 k2 ¼ 0.0016 k2 ¼ 0.000111 k2 ¼ 0.1318 k2 ¼ 0.0062 k2 ¼ 0.00097 k2 ¼ 0.00099 k2 ¼ 0.0096 k2 ¼ 0.231 k2 ¼ 0.0009 k2 ¼ 0.00016 k2 ¼ 0.00013 k2 ¼ 0.0447 k2 ¼ 0.307 k2 ¼ 0000908 k2 ¼ 0.010 k2 ¼ 0.074 k2 ¼ 0.00182 k2 ¼ 0.0577 k2 ¼ 0.000199 k2 ¼ 0.000661 k2 ¼ 0.046 k2 ¼ 0.0035 k2 ¼ 8.107 k2 ¼ 0.002 k2 ¼ 0.210 k2 ¼ 0.0017 k2 ¼ 0.597 k2 ¼ 1.16.104 k2 ¼ 0.005 k2 ¼ 0.0076 k2 ¼ 0.01732 k2 ¼ 0.0021 k2 ¼ 0.0138 k2 ¼ 0.0267 k2 ¼ 0.079 k2 ¼ 0.0290 k2 ¼ 0.00621 k2 ¼ 0.030 k2 ¼ 0.000798 k2 ¼ 0.004935 k2 ¼ 0.0140 kid ¼ 4.03 C ¼ 0.07 k2 ¼ 0.132 k2 ¼ 0.0007 k1 ¼ 0.0208 kid ¼ 3.04 C ¼ 3.35 k2 ¼ 4.17.105 k2 ¼ 0.002 kid ¼ 286.62 C ¼ 801 k2 ¼ 0.00046 kn ¼ 0.0114 k2 ¼ 0.000003. k2 ¼ 0.00406

0.9986 0.999 0.9988 0.999 0.9998 0.981 0.9998 0.999 0.9934 0.999 0.9993 0.993 0.985 0.9993 0.9993 0.9867 0.999 0.99 0.9989 0.9999 0.9999 0.999 1.000 0.9999 1.0000 0.9987 0.999 0.999 0.999 0.9989 0.998 0.9995 0.9672 0.9988 0.9999 0.9999 0.999 0.9998 0.9998 0.999 0.99 0.9986 0.999 0.9989 0.9972 0.9993 0.9672 0.992 0.99 0.9994 1.000 0.96 0.998 0.9981 1.000

[10] [107] [56] [57] [58] [11] [12] [13] [128] [22] [101] [76]

carbon surface [78]. Ghaedi et al. (2012) investigated the adsorption of MB on activated carbon-containing Pd and Au nanoparticles. The studies indicated the important role of hydrogen bonds, attraction and electrostatic repulsion to facilitate the adsorption process [76]. Roosta et al. (2012) shown that the addition of Au metal nanoparticles on activated carbon accelerated the adsorption of MB to reach equilibrium within 1.5 min in comparison to 15e360 min without the presence of Au [91]. Asfaram et al. (2015) have reported that the addition of ZnS and Cu nanoparticles accelerated the time for separation of MB, i.e., to achieve an adsorption equilibrium time of only 2.2 min [95]. Mazaheri et al. (2016) observed that the MB adsorption reached equilibrium within 7.0 min on activated carbon-containing CuS nanoparticles [81].

[25] [59] [29] [104] [103] [89] [37] [38] [39] [120] [93] [67] [40] [41] [95] [68] [111] [112] [69] [79] [113] [96] [80] [81] [97] [124] [114] [82] [42] [71] [72] [45] [47] [48] [49] [115] [84] [116] [117] [125] [73] [109]

4.4. Graphitic carbon and its derivatives Graphitic carbon and its derivatives are the fourth most investigated carbon-based adsorbent group for methylene blue removal. Graphene and graphene oxide are two types of graphitic carbon derived from the treatment of graphite material [101,105], whereas g-C3N4 is another type of graphitic carbon derived from the heat treatment of urea [88] or melamine [99]. Fig. 6 illustrates the methods for synthesis of graphene and graphene composites from graphite. The synthesis of graphene oxide from graphite occurred via oxidation using Hummer's reagent. The degree of oxidation of graphene oxide depends on the source of graphite, the composition of chemical oxidizer, and the length of oxidation time. Yan et al.

10

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

Table 11 Summary of the best-fit parameters of various kinetic models for MB adsorption onto carbon-based adsorbents with temperature variation and calculated activation energy (Ea). Adsorben

Model

T (K)

Parameter

Ea (kJ/mol)

Ref.

Modified expanded graphite powder

Pseudo-second-order

[100]

Pseudo-second-order

18.54

[118]

Modified activated carbon fibers (ACFs)

Pseudo-second-order

28.33

[75]

Magnetic chitosan/active charcoal composite

Pseudo-second-order

30.22

[129]

Activated carbon

Elovich

21.28

[135]

Gold NPs/Activated carbon composite

Pseudo-second-order

¼ 9.319.103 ¼ 5.612.103 ¼ 3.639.103 ¼ 0.00182 ¼ 0.00254 ¼ 0.0078 ¼ 0.000336 ¼ 0.000398 ¼ 0.000490 ¼ 0.00126 ¼ 0.00163 ¼ 0.00273 u ¼ 0.91 m ¼ 4.64 S* ¼ 1.311.105 S* ¼ 0.998

2.14.108

Carbon nanotubes

293 318 343 273 298 333 308 318 328 308 318 328 298 308 323 293 303 313

41.38

[91]

k2 k2 k2 k2 k2 k2 k2 k2 k2 k2 k2 k2

Table 12 The summary of the thermal treatment of various biomass/biomass waste feedstocks to carbon materials materials for methylene blue adsorbent, which published in the some papers between 2008 until 2019. Feedstock

Preparation condition

Producta)

Ref.

Dried powder of reed Dried powder of reed straw Dried powder of municipal solid wastes (60% paper, 25% yard wastes and 15% textiles. Dried powder of peanut shell (activated in 1.0M Zn(NO3)2 solution) Dried powder of weeds

500  C, in a tubular furnace for 2 h with an atmosphere of N2. 500  C, in a quartz porcelain boat, in a furnace for 2 h with an atmosphere of N2 400e500  C, using a pressure batch reactor, with nitrogen gas at 10 psi.

Char Char Char

[62] [86] [63]

550  C, in a lab-scale tubular reactor for 1 h with an environment of N2

Char

[64]

500  C, in a horizontal stainless-steel tubular reactor (7.0 cm diameter x 100 cm length) under Char nitrogen atmosphere for 1 h Dried powder of the loofah sponge (activated in 600  C, 800  C, and 1000  C, in a quartz tube furnace (inner diameter of 60 mm and a tube length Granular of 1000 mm) min in argon atmosphere for 1 h. activated 10% NaOH solutions with ultrasonic bath) carbons  Dried powder of the Date press cake 500 C, under nitrogen flow for 2 h. Carbonized material Dried powder of corncob 400e500  C, in a two-neck round bottom quartz flask, inside a microwave cavity oven (heating Char area of the oven is 46.1 cm
28.9 cm
37.7 cm), a maximum output power of 800 W, with an atmosphere of N2 for 10 min. Dried powder of date palm leaflets 500  C, in a carbon steel tube (internal diameter 5.1 cm and length 61 cm, in a tube furnace Char under nitrogen atmosphere for 2 h.  Carbonized Dried powder of spent coffee grounds 450 C, in a horizontal electric furnace with a quartz tubular reactor, 2 h under a nitrogen atmosphere product Char Dried powder of the factory rejected tea 200  C, in 100 mL distilled water, a 200 mL stainless steel hydrothermal reactor for 5 h Dried powder of tea waste of household uses 200  Ce400  C, in a horizontal temperature programmable furnace with 1 h dwelling time in Carbonized impregnated with 85% phosphoric acid each 100  C interval, under nitrogen (N2) atmosphere sample Dried powder of macadamia nut endocarp 500  C, in a stainless steel reactor, using a 2.45 GHz conventional microwave oven, 2 h under N2 Char atmosphere Dried powder of tea waste impregnated with 85% 450  C, in a quartz boat, fixed bad quartz tubular furnace under 150 ml/min N2 flow, for 1 h. Activated carbon phosphoric acid Carbonized Dried powder of coconut shells 600  C, in stainless steel reactor (600 mm
40 mm), in absence of air for 4 h. sample Dried powder of Peanut sticks 400  C, in a well-sealed stainless steel tube, in a muffle furnace, in the absence of air for 2 h. Physically activated carbon  Dried of medical cotton balls (soaked with ZnCl2 400e700 C, sintered in argon for 1 h Activated fiber carbon solution) a

[65] [73]

[51] [48]

[78] [141] [41] [67] [143] [36] [90] [135]

[27]

Terminology of product from the author of related paper.

investigated the degree of oxidation of graphene oxide and its adsorption capacity for removal of MB by oxidizing graphite with KMnO4. The studies revealed the degree of MB uptake were exponentially increased with the degree of oxidation of the graphene oxide [105]. Modification of graphite with metal oxides TiO2, MgO, Fe3O4, and carbon nanotubes have been reported to form metal oxide/graphite composites [103]. GO/MgO nanocomposites produced via impregnation of MgO nanoparticles on GO that was

derived from graphite oxidation [97]. Composite carbon graphitic using g-C3N4 with biochar (biochar/g-C3N4 composite [88]), NbO (Polyoxoniobate/g-C3N4 nanoporous) [99]) produced composites with increased adsorption capacity of methylene blue. Table 6 shows the structural properties of carbon graphite and its derivatives following variation of modification methods for removal of MB from water. The adsorption capacity of MB from graphite based adsorbents also varies greatly, with the highest

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

11

Fig. 4. General procedure for the synthesis of activated carbon from biomass, biomass waste, and industrial waste. Fig. 6. General procedures for the synthesis graphene, graphene oxide, and their modification as carbon-based adsorbents.

Fig. 5. Modification process of activated carbon to enhance the adsorption of MB.

adsorption capacity were in the range 500e900 mg/g on adsorbent with surface area less than 500 m2/g. Li et al. (2013) observed high adsorption capacity of MB on graphene oxide in comparison to carbon nanotubes, but lower than activated carbon [30]. The high adsorption capacity of graphene oxide was associated with the large pore diameter of 17.3 nm in comparison to carbon nanotubes ~12.1 nm. The studies also indicated that the adsorption density per unit area on graphene oxide was 7.5 mg/m2, significantly higher in comparison to carbon nanotubes and activated carbon, with the respective values of 1.23 mg/m2 and 0.16 mg/m2. The interaction of MB and graphite was proposed to occur via pp interaction and electrostatic attraction on graphene oxide surface [29]. Zhao and Liu (2009) observed that the adsorption capacity of MB on graphene oxide was significantly enhanced at high pH due to the formation of negatively charged surface that increased the electrostatic forces with MB [100]. Similar observation was reported by Ghaedi et al. (2014) on the adsorption of MB and brilliant

green on graphite oxide [104]. However, Yan et al. (2014) reported that the MB adsorption capacity in graphene oxide increased with the degree of oxidation of graphene oxide, but relatively unaffected with the changes of pH. The studies also concluded that the MB adsorption on graphene oxide occurred through the interaction of p-p in the non-oxidized area of graphene oxide and via the hydrophilic electrostatic attraction in the oxidized region [105]. Liu et al. (2012) investigated the reduction of graphene oxide using hydrazine to graphene for adsorption of MB and indicated that no correlation between the MB adsorption capacity and the pH of the solution [101]. Padhi et al. (2016) proposed that the adsorption of MB on the surface of graphene oxide occurred via electrostatic interactions following investigation using Raman spectroscopy and infrared analysis [106]. Lunhong Ai and Jing Jiang (2012) examined the adsorption of MB in graphene oxide/carbon nanotube composites, and the results showed that the adsorption capacity improved with increasing the pH of the solution. The studies also revealed significant enhancement of the pH of the solution following adsorption process when the initial pH of MB solution was within 2e6. However, no significant differences on the pH of the solution when the initial pH of the solution was above 6. This observation was further reinforced the conclusion that the adsorption mechanism involved electrostatic forces between adsorbents and adsorbates [102]. Wang et al. (2014) produced magnetic particles Fe3O4/carbon composites, in which the addition of magnetic properties to the carbon adsorbent facilitated the process for separation of the adsorbed MB from carbon [103]. Mahdi Heidarizad and S. Sevinç € rengo €r (2016) synthesized graphene oxide/MgO composites as MB o adsorbent that showed the addition of optimum amounts of MgO to graphene oxide increased the adsorption capacity of MB. However, the adsorption decreased at high loading of MgO. The studies also revealed that the adsorption of MB was dependent on the pH of the solution in which at below pH point of zero charges, pHpzc the adsorption occurred via hydrogen bonds and p-p interactions, meanwhile at high pH of the solution, the interaction occurred via electrostatic attraction [97]. Wang et al. (2016) investigated the

12

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

effect of microwave-assisted and thermal reduction methods during the synthesized graphene oxide/TiO2 composites. The microwave assisted method shortened the synthesis time of graphene oxide/TiO2 composites and also increased the adsorption capacity of MB (845.6 mg/g) in comparison to the thermal reduction methods (467.6 mg/g) [96]. 4.5. Porous carbon materials Porous carbon material is the fifth most investigated carbon adsorbent for MB removal with the synthesis is often utilized carbon precursors such as furfuryl alcohol [92], sucrose [94,95], glycerol [99], resorcinol/formaldehyde [96], metal-organic framework (MOF) materials [101], and polymers [94,95,100,102]. The resulting carbon was also undergone activation using chemical activators such as HF, KOH and H2SO4. The use of template or porous forming agent were important to control the pore structure of carbon. Carbon precursor, activating reagent, structural properties and adsorption capacity of porous carbon materials from researches published in 2008 until 2019 were summarized in Table 7. The choice of carbon precursor was significantly contributed to the structural properties and surface functionality of carbon. Fig. 7 illustrates the utilization of different type of carbon precursor and the activation process for production of activated porous carbon adsorbents. For example, the synthesis of carbon from Chitosan by treatment with KOH at 900  C produced three-dimensional activated porous carbon. The studies indicated that the use of chitosan as precursor to produce the three dimensional porous carbon allowed high adsorption capacity and fast removal of MB from wastewater [109]. Yan et al. (2009) synthesized mesoporous carbon from furfuryl alcohol (FA) using zeolite X as template followed by acid and base pre-treatment. The removal of zeolite X template was carried out using hydro fluoride acid (HF). The studies revealed the formation of mesoporous carbon with pore diameter of 3.8 nm. The performance on MB removal was varied depending on the treatment, in which carbon following alkaline pre-treatment has high BET surface area and adsorption capacity (936 m2/g, 436.55 mg/g) in comparison to the carbon treated with acid (764 m2/g, 262.87 mg/g) [107]. Derylo-Marczewska et al. (2010) produced porous carbon from sucrose using silica as template with two types of Pluronic block copolymers (PE9400 with M ¼ 4600 and PE6800 with M ¼ PE6800)

as pore directing agents [98]. The template was later removed using KOH solution. The results revealed the effect of the molecular weight of pore directing agents in which the PE6800 produced mesoporous carbon with pore diameter of 4.1 nm, the surface area of 705 m2/g, and the adsorption capacity of 499.04 mg/g. Meanwhile PE9400 produced carbon with micropore size of 1.8 nm with low surface area and MB adsorption capacity [98]. Marczewski (2010) also conducted studies on the effect of aging temperature on the formation of porous carbon using silica templates. The results showed that increasing the aging temperature affected the formation of surface area, pore diameter, and adsorption capacity of MB [110]. Kazak et al. (2017) synthesized porous carbon from sucrose and incorporated with red mud for the formation of porous carbon composites. The addition of red mud increased the surface area and the pore size of carbon introduced micropores and mesopores structures. The red mud/carbon composites showed adsorption capacity of MB of 100 mg/g [114]. Narvekar et al. (2018) produced porous carbon materials from glycerol, without the use of templates and pore directing agents. Transformation of glycerol to porous carbon occurred by annealing at 120  C and 350  C. Characterization data showed that activation at 350  C produced large surface area carbon (464 m2/g) meanwhile activation at 120  C reduced the surface area of carbon to ~ 21 m2/g. However the adsorption capacity of MB was higher for carbon produced at 120  C with ~865 mg/g meanwhile only 156 mg/g was measured on carbon produced at 350  C. The studies also revealed that temperature for thermal activation showed negligible effect on the formation of pore structure with average pore diameters were analysed at 3.7 nm. The high adsorption capacity of the activated adsorbent produced at 120  C was related to the increased electrostatic interaction between the sulfonate group on the carbon with MB [115]. Jia et al. (2016) synthesized activated carbon microspheres from polyvinyl alcohol precursors, through sulfonation and carbonization methods, with the MB adsorption capacity of 602.4 mg/g at 25  C and 925.9 mg/g at 45  C. The addition of metal cations on carbon microspheres decreased the ability of the adsorbent to remove MB. The studies suggested the mechanism of MB adsorption occurred via electrostatic attraction between the adsorbent and the MB [111]. Zhou et al. (2018) also synthesized porous carbon from polyvinyl alcohol with using manganese carbonate, manganese oxalate, and manganese acetate as template. The template was

Fig. 7. The synthesis porous carbon from various carbonaceous precursor materials.

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

removed by treatment with H2SO4 at high temperature. The adsorption studies on MB showed that manganese oxalate produced carbon with high adsorption capacity ~2936 mg/g and the value was related to the high surface area and the high mesoporous volume of carbon (2138 m2/g, 3.54 cm3/g) [116]. Simonetti et al. (2016) synthesized carbon/TiO2 composites as MB adsorbents, using resorcinol-formaldehyde polymers and titanium isopropoxide as carbon and TiO2 precursors. The results revealed the addition of TiO2 changed the pore size of carbon from microporous to mesoporous structures, thus increasing the adsorption capacity of MB. The FTIR analysis confirmed the MB adsorption on carbon occurred through p-p interaction between the aromatic rings of MB and the carbon layers [112]. Chen et al. (2018) synthesized porous carboncontaining nitrogen through carbonization of ZIF-8 under the flow of argon and steam. The results of the characterization indicated the formation of high surface area of carbon ~1694 m2/g with pore diameter of 1.5 nm, and the adsorption capacity of MB at 100.2 mg/g [117]. 4.6. Carbon nanotubes Researches on carbon nanotubes as adsorbents for MB involved modifications of the structural properties to enhance surface functionality [122,125]. Carbon nanotube was also investigated following combination with other materials to form composites [119,120,123,125]. However, investigation on carbon nanotube as adsorbent for MB removal is relatively scarce in comparison to previous type of carbon adsorbent discussed earlier. Table 8 summarized researches on carbon nanotubes as adsorbent for MB removal from wastewater. General procedures for production of carbon nanotube adsorbent is simplified in Fig. 8 with most researches involved modification prior to the adsorption process. For example, modification of multiwall carbon nanotubes (MWCNTs) with calcium alginate was carried out by dispersing the MWCNTs with DI water suspension to form colloidal solution. The CaCl2 solution was added to form composite beads containing MWCNT particles, and non-crosslinked calcium ions. Investigation onto MB removal from water showed enhancement on the adsorption of MB

13

following impregnation with calcium alginate beads due to the enhanced dispersion and stability of carbon nanotubes [125]. Carbon nanotube was also produced using gas as carbon precursor as shown by Yao et al. (2010). Carbon nanotubes was obtained from acetylene gas, with the adsorption capacity at 298 K was 46.2 mg/g [118]. Li et al. (2013) also synthesized carbon nanotubes from methane and the adsorption studies were compared with graphene oxide and activated carbon. The adsorption capacity of carbon nanotubes was 188.68 mg/g [29]. Robati et al. (2016) synthesized nanocomposite multi-walled carbon nanotubes functionalized with thiol through chemical reactions with cysteamine hydrochloride in ethanol. The adsorption capacity increased with the presence of thiol functional groups in multi-walled carbon nanotubes [122]. Deng et al. (2012) [119] introduced cellulose and gum to carbon nanotubes to form hybrid material for MB adsorbents and the results showed the modified material increased MB adsorption capacity to 308 mg/g. The studies also indicated that the adsorption capacity increased with pH due to MB absorption occurred through electrostatic interactions. Gong et al. (2015) synthesized porous cup-stacked carbon nanotubes (P-CSCNT) from polypropylene precursors with KOH as chemical activators with the results showed the surface area of 558.7 m2/g and the adsorption capacity in MB of 319.1 mg/g. Gong et al. (2015) also concluded that the MB adsorption in P-CSCNT occurred via multi step interactions such as adsorption of MB within the pore of carbon nanotube, formation of hydrogen bonding, p-p interaction and electrostatic interactions [121]. Z. Zhang and X. Xu (2014) modified carbon nanotubes with poly (sodium 4-styrene sulfonate) into CNT/PSS composites which increased the adsorption capacity of MB. The adsorption process involved p-p electron interactions between MB aromatic rings and carbon nanotubes and electrostatic interactions between the positive charge of MB and the negative charge of SO3 group in poly (sodium 4-styrene sulfonate) [120]. Wang et al. (2018) produced composites between multiwall carbon nanotubes with calciumalginate by impregnation method. The results of the MB adsorption showed high adsorption capacity of the composites (1189 mg/ g) compared to the multiwall carbon nanotubes (33.4 mg/g) and the alginate (1144.7 mg/g). Enhanced adsorption capacity was due to the synergistic effect between the interaction of p-p electrons in aromatic rings of MB and the electrostatic attraction between the functional groups of carbon nanotubes composites and MB [125]. Duman et al. (2016) introduced carrageenan and magnetic nanoparticles Fe3O4 into magnetic oxidized multiwalled carbon nanotubes to produce magnetic nanocomposites for adsorption of MB. Characterization studies showed that the addition of carrageenan and Fe3O4 reduced the surface areas from 237.5 m2/g to 142.2 m2/g and also reduced the mesoporous volume of adsorbent from 1.970 cm3/g to and 0.845 cm3/g, which have detrimental effect to the adsorption capacity of MB. However, the presence of magnetic nanoparticles facilitated the separation process of MB without filtration process. The mechanism of MB adsorption was proposed to follow the interaction between the p-p electrons and electrostatic attraction [124]. Manilo et al. (2016) modified multi-walled carbon nanotubes with Laponite synthetic clay to produce composite materials for MB adsorbent. The composite improved the adsorption capacity of multi-walled carbon nanotubes from 72 mg/ g to 212.75 mg/g [123]. 5. Thermodynamic and kinetic of methylene blue adsorption on carbon

Fig. 8. The general method for the synthesis and modification of carbon nanotubes as MB adsorbents.

Thermodynamic in an essential aspect for understanding the dynamics of MB adsorption on carbon surface. Investigation on the adsorption capacity at various temperatures allowed the

14

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

calculation of thermodynamic parameters, such as the enthalpy and the entropy of adsorption and also the Gibbs free energy. The kinetic study is vital to provide insight into the adsorption process as a function of time, which is the adsorption rate where the value is proportional to the adsorption rate constant (k). The activation energy of adsorption (Ea), which is the minimum energy requirement for adsorption is determined when the adsorption rate is measured at various temperatures.

MB adsorption isotherm is an integral part of thermodynamic adsorption, which described the equilibrium relationship between the amount of MB adsorbed on the adsorbent and the amount of adsorbates in the solution at certain temperature. The adsorption isotherm also provides physicochemical information that is useful for evaluation of the adsorption process. Several models of adsorption isotherms were investigated to describe the adsorption of MB, but Langmuir model (Equation (1)) and Freundlich (Equation (2)) were mostly applied in order to describe the adsorption of methylene blue [125]. The Langmuir model presumed that the adsorption on homogenous surface occurred via the formation of monolayer of adsorbates without further interactions between the adsorbates. The Freundlich model however is based on the assumption that the adsorption of sorbent ions occur on heterogeneous surface and may involve a multilayer process. Although the Langmuir and the Freundlich models cannot provide conclusive proofs of the adsorption mechanisms, they were proven useful to gain understanding on the adsorption mechanisms [125]. The Langmuir and the Freundlich models were widely used to describe the isotherm adsorption mainly due to the procedures were simple and the models represented adsorption process on both homogeneous and heterogeneous conditions. Studies by Altenor et al. employed Redlich e Peterson model which incorporated the features of the Langmuir and Freundlich isotherms into a single equation (Equation (3)) [43]. The model was adapted to fit the adsorption of MB on activated carbon derived from vetiver roots. The studies also investigated Brouers e Sotolongo isotherm (Equation (4)) [43]. Combinations between Langmuir and Freundlich isotherms were also employed to describe the adsorption isotherms of MB on carbon such as Sips isotherm (Equation (5)) [132], DubinineRadushkevich isotherm (Equation (6)) [133], Tempkin isotherm (Equation (7)) [133], Toth isotherm (Equation (8)) [134], Khan isotherm (Equation (9)) [133], Langmuir-Freundlich (Equation (10)) [135], and Frumkin (Equation (11)) [40,136].

Q m KL Ce 1 þ KL Ce 1=n

qe ¼ KF C e qe ¼

KRP Ce

1 þ aRP C be



 qe ¼ Q m 1  exp  Kw C ae qe ¼

Qm Ks C ns e 1 þ Ks C ns e

  2 3 RTln 1 þ C1e 6 7 6 7 qe ¼ Q m exp6  7 4 5 2E2

qe ¼

(1)

(2)

(3)

(4)

(5)

qe ¼

qe ¼

(6)

RT lnðKTe Ce Þ b

(7)

Q m Ce 1=t KT þ C te

(8)

Q m bK C e ð1 þ bK Ce ÞaK

(9)

qe ¼ 

5.1. Adsorption isotherm of methylene blue on carbon adsorbent

qe ¼

2

Q m ðKLF Ce Þ1=n 1 þ ðKLF Ce Þ1=n

KCe ¼

q

1q

expð2εqÞ

(10)

(11)

where qe(mg.g1) is the adsorption capacity; Qm(mg.g1) is the maximum adsorption capacity; Ce(mg.L1) is the equilibrium concentration after the adsorption or desorption; KL(L.mg1) is a Langmuir constant; KF(mg11/n.L1/n.g1) is the Freundlich adsorption constant; 1/n (dimensionless) is the adsorption affinity, KRP(L.g1) and aRP(Lb.mgb) are the RedlichePeterson isotherm constants, b is the exponent which generally lying between 0 and 1 (It has two limiting behaviours: Langmuir form for b ¼ 1 and Henry's law form for b ¼ 0), KW(Weibull constant) ¼ K/Qm where K]KF is the Freundlich constant for low Ce, at a given temperature and the exponent is a measure of the width of the sorption energy distribution and therefore of the energy heterogeneity of the sorbent surface, KS (Lnsmgns) is the affinity constant and nS describes the surface heterogeneity, E is energy of adsorption, KTe is equilibrium binding constant (Lg1), b is related to heat of adsorption (J.mol1), R is the gas constant (8.314
103 kJ K1 mol1), T is the absolute temperature (K), KT is the Toth model constant, t the Toth model exponent (0 < t  1), bK is the Khan model constants, aK is the Khan model exponent, KLF is Langmuir-Freundlich constant (Lmg1), q is the fractional occupation (q ¼ qe/Qm), K is. the adsorption equilibrium constant, ε: interaction coefficient (ε > 0 indicates attraction, while ε < 0 indicates repulsion. while ε ¼ 0 indicates no interaction between the adsorbate species). The adsorption isotherm is an equilibrium process so that the free energy of the process follows Equation (12) where K is the equilibrium constant of adsorption (dimensionless), R is the universal gas constant (8.314 J mol1 K1), T is the absolute temperature (K), and DGo is the free energy change of adsorption (J mol1). The other thermodynamic parameters of adsorption can be calculated based on Equations (13) and (14), where DHo and DSo are the enthalphy change (J mol1) and the entropy change (J mol1 K1) of adsorption [137]. Table 9 summarized the thermodynamic parameters and the best-fitted isotherm model of MB adsorption on carbon-based adsorbents. The experimental value of K equilibrium adsorption constants can be calculated based on different method which Liu (2009) has clearly explained the method for calculation of the adsorption equilibrium constant [138].

DGo ¼  RTln K

(12)

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

DGo ¼ DHo  T DSo ln K ¼

DSo R



DH o 1 R

T

(13) (14)

energy indicated the accessibility of the adsorption to occur on the carbon surface. In general for chemical reaction, the activation energy is obtained using the Arrhenius method (Equation (22) or (23)) [118]. In the case of molecular adsorption, the Arrhenius method was modified with statistical mechanic's approached which used Equations (24)e(26) [91,135].

Based on the summarized information of the thermodynamic parameters in Table 9, the adsorption of MB on carbon-based adsorbents can occur as spontaneous process or as endothermic process. The increased randomness of the carbon surface allowed adsorption to follow Langmuir adsorption isotherm. Furthermore, according to the magnitude of the Gibbs free energy and the enthalpy change of adsorption, MB adsorbed on carbon adsorbents via physisorption process. The adsorption with enthalpy less than 84 kJ/mol and the Gibbs free energy between 20 and 0 kJ/mol were generally considered as physisorption process, meanwhile the enthalpy of the adsorption and the Gibbs free energy for the chemisorption process were often between 84 and 420 kJ/mol and 80 until 400 kJ/mol [139].

lnð1  qÞ ¼ ln S* þ

5.2. Kinetic modelling of methylene blue adsorption on carbon

q¼ 1

  Ea k ¼ A:exp  RT ln k ¼ ln A 

(22)

Ea RT

(23)

  Ea S* ¼ ð1  qÞexp  RT



In order to gain understanding on the mechanism of MB adsorption from an aqueous solution onto solid adsorbent, two kinetic models were mainly investigated; the pseudo-first-order model of Lagergren (Equation (15) or Equation (16)) and the pseudo-second-order model of Ho (Equation (17) or Equation (18)) [117,125]. Researches have also suggested that the intra-particle diffusion model of Weber and Morris (Equation (19)) [51], the Elovich model (Equation (20)) [125], and the Ritchie model (Equation (21)) [125] were also useful to describe the kinetic adsorption of MB on carbon.

15

Ce Co

Ea RT

(24)

(25)

(26)

qt ¼ qe ð1  expð  k1 tÞ

(15)

lnðqe  tÞ ¼ lnqe  k1 t

(16)

where k, Ea, A, S*, and Co are the rate constant of adsorption, the activation energy (kJ/mol), the Arrhenius factor, the sticking probability (Its value lies in the range 0 < S* < 1), and the dye concentration at initial (mg.L1), respectively. Tables 10 and 11 summarized the parameters of kinetic models that best fitted to the process of MB adsorption on the carbonbased adsorbents. Majority of the MB adsorptions followed the pseudo-second-order kinetic model and only few occurred via different kinetic models such as Intra-particle diffusion, Elovich, and Ritchie models. The calculated activation energy of the adsorption (Table 11) indicated that MB adsorption occurred via physisorptions process with activation energy of Ea  40 kJ/mol. However some studies also indicated that the adsorption occurred via chemisorptions with activation energy of Ea > 40 kJ/mol [129].

(17)

6. Methods for characterization of carbon adsorbent

qt ¼

k2 q2e t 1 þ k2 qe t

t 1 t ¼ þ qt k2 q2e qe

(18)

qt ¼ ki t 1=2 þ C

(19)

qt ¼

1

u

lnðmut þ 1Þ

1 1m  km t qt ¼ qe  q1m e 1m

(20)

(21)

where qt(mg.g1) and qe(mg.g1) are the amounts of MB adsorbed at given time t and at equilibrium, respectively; k1(min1), k2(g.mg1min1), and km(gm1mg1mmin1) are the pseudo-firstorder, pseudo-second-order, and Ritchie mth-order adsorption rate constants, m(mg g1 min1) is the initial adsorption rate; and u(g mg1) is the desorption constant. The adsorption of MB on carbon adsorbent is an energetic process in terms of the kinetic of adsorption. MB molecule adsorbed on carbon surface has to overcome several barriers, such as the angle orientation, the length of the interaction bond, and the angle of the MB bond, that were consequently contributed to the energy barrier or the activation energy of the adsorption. The activation

Analytical method used for characterization of carbon-based adsorbent and the information obtained from each methods in the literatures published between 2008 until 2019 were summarized in Table 13. In general analytical methods were used to investigate the physical and chemical properties of carbon, and also to study the interaction between carbon and methylene blue. The frequency of different type of analytical methods used in the work included in the review were tabulated in Fig. 9. FTIR analysis, N2 adsorption-desorption method, and SEM have been widely employed for characterization of carbon adsorbent. FTIR analysis was used to provide evidence on the functional group presence on carbon surface. Information on the mechanism of MB adsorption on carbon surface was also obtained by infrared analysis following analysis of the carbon before and after exposure with MB. Surface properties of carbon was also analysed using X-ray photoelectron spectroscopy (XPS). XPS is a surface sensitive technique that often used to provide the composition of element on the surface and also distinguished the functional groups that occurred on the carbon surface. Since adsorption of MB occurred via physical interaction that occurred on the surface, XPS is able to provide information of the surface properties and functionally of carbon in comparison to FTIR analysis that is more towards analysis of bulk structure. N2 adsorption-desorption method is a crucial tool to provide information on the surface area and the porosity of carbon, due to the adsorption capacity is mostly governed by such properties.

16

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

Table 13 Characterization techniques of the carbon-based materials as the adsorbents for methylene blue from water in the number of papers between 2008 until 2019. Method

Information

References

Fourier transform infrared (FTIR) spectroscopy

Functional groups identification of adsorbent, before and [12e14,22,27,29e31,34e36,41,42,45,47e52,54,55,57,59,61e64,66,67,71 after adsorption e74,78,79,82,84e86,89,90,92], [93e95,97,101e103,105,106,109,111 e116,120,124,128,129,135,140,142,144e151] [11e14,27,29,30,33e39,41,42,45,47e52,54,55,59,61e63,66,68 Scanning electron microscope  Surface morphology analysis of adsorbent e76,78,81,82,84], [85e99,102,103,109,111e115,120 (SEM)  Shape and size of adsorbent pores e122,124,128,129,135,142,144e149], [151e154]  Particle size analysis of adsorbent Energy Dispersive X-Ray (EDX) Surface elemental microanalysis of adsorbents [14,27,36,49e51,55,66,71,74,78,85,87,90,98,115,129,140,146,151] Analyzer Transmission electron Inner morphology analysis of adsorbent [29,69,75,76,81,91,97,99,101,102,105,106,116,117,121,124,129] microscopy (TEM) X-ray diffraction (XRD) Crystal structure analysis of adsorbents [27,40,50,59,62,63,67,69,73,76,78,79,81,84e86,89,92,93,95e99,101 e103,105,106,109,111,112,115e117,121,124,128,142,146], [148,149,154] Electron diffraction (ED) Lattice structure analysis of nanoparticles in adsorbent [76,91] X-ray photoelectron Surface elemental content and surface functional groups [42,57,69,97e99,105,117,120,121,143,144,146,148,154] spectroscopy (XPS) percentage of adsorbent [27,69,96,101,105,106,113,116,117,121,142] Raman spectroscopy (RS) Ordered and disordered crystal structures and distinguish the single-, bi-, and multilayer characteristics of adsorbent N2 adsorption-desorption Surface area and porosity of adsorbent [11,13,14,22,27,29,33e38,40e42,45,47,50e59,61e65,67e69,71e75,78,79,82], (NAD) analysis [84e87,89e94,101,102,108,109,112e117,120,121,124,129,135,140,142 e144,146e152,154,155[84e87,89e94,101,102,108,109,112 e117,120,121,124,129,135,140,142e144,146e152,154,155] Thermal analysis (TGA/DTG/ The mass loss characteristic of adsorbent related to [50,55,64,67,72,73,78,84,85,92,96,97,108,111,114 DTA/DSC/DMA) thermal degradation e117,120,121,124,129,142,146,151] X-ray fluorescence (XRF) Elemental analysis of adsorbent [103] spectrometry Particle size distribution of adsorbent [36,70,80,103,129,142,151] Laser particle size (LPS) analyzer or dynamic light scattering (DLS) Zeta potentials (ZP) analyzer Surface zero charge pH of adsorbents [13,14,29,33,40,47,50,51,53e55,57,62e64,72,74,76,78,90,94,105,114,128,142 e144,146,148,151,155] Vibrating sample Magnetic properties of adsorbent [124,142] magnetometer (VSM) Elemental analyzer (EA) Elemental content mass percentage of adsorbents [36,39,45,55,59,63,65,78,86,92,146e148,150,152] Boehm titration (BT) Surface pH, surface basicity and acidity groups content of [55e57,65,113,124,143] adsorbents NaOH/HCl titration (ABT) Total acidity and basicity of adsorbents [22,53]

Fig. 9. Analytical methods for characterization of carbon adsorbent and the frequencies for each methods employed in the researches published from 2008 to 2019.

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

17

Table 14 Regeneration methods for carbon-based materials as methylene blue adsorbent and usability level after the recycling process. Regeneration techniques

Devices for regeneration process

Thermal degradation under low oxygen or N2 (inert) atmosphere.

A 600 W modified domestic microwave 80%e90% uptake after five times uses oven with a heating frequency of 2.45 GHz. Glassware, stirrer, centrifuge 90%e64% removal after four e seven recycles

Desorption in the mixture of ethanol and chloride acid solution (pH 2.0) Desorption in the mixture of ethanol and NaOH solution Glassware, stirrer, centrifuge Thermal annealing at 300  C for 6 h under argon atmosphere. Furnace/Oven Desorption in methanol Photo degradation in ethanol aqueous solution Desorption in 0.1M chloride acid solution Continuous extraction in the liquid-solid system: in hot water or in hot DMSO, with and without annealing 300  C

Glassware, stirrer, centrifuge 450 W medium pressure quartz mercury vapor lamp Glassware, stirrer, centrifuge Soxhlet

Desorption in 0.1M HCl, H2SO4, and NaOH Desorption in the mixture ethanol/acetic acid eluent (v/v:9/ 1) with ultrasonication Desorption in 1.0M acetic acid solution Desorption in desorbing agents (distilled water, 0.1 M of EDTA, 0.1 M of hydrochloric acid, ethyl alcohol, and 0.1 M of oxalic acid) Desorption in deionized water Desorption in methanol and in 0.5M NaCl solution

Glassware, stirrer, centrifuge Glassware, stirrer, centrifuge

Desorption in anhydrous ethanol

Glassware, stirrer, centrifuge

Glassware, stirrer, centrifuge Glassware, stirrer, centrifuge, Ultrasonic sonicator Glassware, stirrer, centrifuge Rotary shaker

Usability level of adsorbents

References [53]

[69,102,103,140]

91% recovery after four recycles 96% of original adsorption capacity after five cycles, 91% after ten cycles 75% removal after six cycles 86.6% removal after five cycles

[105] [121]

>75% removal after five cycles In water with annealing was the best regeneration, >70% of original adsorption capacity after two cycles In 0.1M HCl was the best desorption 60% removal after three cycles

[114,142,154] [148]

[42,94,141] [96]

[49] [66]

>80% removal after two cycles [149] Ethyl alcohol was the desorbing agent with >90% [109] removal after six cycles 30% removal after three cycles 61.54% in methanol, 64.23% in NaCl solution, of original adsorption capacity after six cycles. Adsorption capacities are 85 mg/g in the first cycle and 70 mg/g in the fifth cycle

[125] [85] [98]

Scanning electron microscopy, SEM is a non-destructive method to obtain the morphology, size and when equipped with EDX provide information on elemental composition of carbon. Similar information however at nanoscale resolution can be obtained using transmission electron microscopy, TEM. The rest of the analytical methods used for characterization of carbon and the information that were obtained from the analysis were summarized in Table 13.

methylene blue was weakly bonded to the surface of the adsorbent. Otherwise, when the desorption was carried out in acidic solution, the methylene blue dominantly bonded on carbon by the ion-exchange mechanism [140]. However, Ye et al. (2016) reported that the use of ethanol for desorption of methylene blue from carbon material showed similar desorption efficiency when using 0.1 M chloride acid solution [79].

7. Carbon-based adsorbent reusability

8. Conclusions

The regeneration of the adsorbent after reaching the saturation point is essential in order to minimize the operational costs, to reduce the accumulation of solid waste from the used adsorbent and to increase the reusability of adsorbents. Regeneration process involved desorption of methylene blue from carbon adsorbent which is also useful to provide insight into the mechanism of MB adsorption. Table 14 summarized the methods that have been utilized for desorption and regeneration of MB from carbon adsorbents. In general, regeneration methods can be divided into two types; degradation and desorption. Degradation method is essentially involved decomposition of adsorbed MB either using thermal annealing at high temperature [121], microwave irradiation [53] or photodegradation [96], with more 80% of carbon retained the initial adsorption capacity. The second type of regeneration is via desorption method. The desorption method have been widely investigated to regenerate carbon adsorbent and also to recover the MB. However, the efficiency of the regeneration process via desorption is strongly depended on the physical and chemical properties of the carbon and the liquid medium. Methanol, ethanol, ethyl alcohol, oxalic acid, acetic acid, HCl and NaOH were among the most investigated medium used to facilitate the desorption of MB and showed significantly higher carbon reusability in comparison with desorption using water [125]. Liu et al. (2014) have stated that when the desorption of MB from carbon was carried out in deionized water medium, the

The review of researches reported from 2008 to 2019 indicated significant growth of interest on the absorption studies of MB using carbon-based adsorbent. Carbon-based adsorbents have an excellent potential for isolating MB from aqueous solutions on the laboratory scale. The fabrication of the various carbon adsorbent, such as pyrolysis and hydrothermal carbonization of biomass and biomass waste, porous carbons from metallic organic frameworks (MOFs), g-C3N4 from urea or melamine, graphite, graphene, carbon nanotubes, and their composites, provided the route to promote the adsorption capacity. Natural biomass is the most abundant economic sources for the synthesis of carbon, which usually converted into activated carbon or biochar. The review also suggested that the adsorption capacity of carbon improved with increasing the surface area but showed little improvement with increasing the pore size. The interaction between methylene blue and the surface of carbon material occurred via variety of ways, including the interaction of p-p electron of aromatic ring, the electrostatic attraction between cationic and anionic groups, the formation of hydrogen bridges, and the dipole-dipole interactions. Investigation of regeneration of the carbon adsorbent following the adsorption process is divided into degradation and desorption processes, which is and important aspect of investigation in order to increase the re-usability of carbon adsorbent. Desorption of MB form carbon also provide information on the interaction between carbon adsorbent and MB adsorbate.

18

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

Declaration of interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgment Authors would like to acknowledge funding from Institut Teknologi Sepuluh Nopember, Indonesia; Laboratory Research Grant No. D22018. References [1] G. Eshaq, A.E. Elmetwally, Bmim[OAc]-Cu2O/g-C3N4 as a multi-function catalyst for sonophotocatalytic degradation of methylene blue, Ultrason. Sonochem. 53 (2019) 99e109, https://doi.org/10.1016/ j.ultsonch.2018.12.037. [2] A. Mosbah, H. Chouchane, S. Abdelwahed, A. Redissi, M. Hamdi, S. Kouidhi, M. Neifar, A.S. Masmoudi, A. Cherif, W. Mnif, Peptides fixing industrial textile Dyes : a new biochemical method in wastewater treatment, Hindawi J. Chem. 2019 (2019), https://doi.org/10.1155/2019/5081807. [3] P. Senthil Kumar, S.J. Varjani, S. Suganya, Treatment of dye wastewater using an ultrasonic aided nanoparticle stacked activated carbon: kinetic and isotherm modelling, Bioresour. Technol. 250 (2018) 716e722, https:// doi.org/10.1016/j.biortech.2017.11.097. [4] V. Katheresan, J. Kansedo, S.Y. Lau, Efficiency of various recent wastewater dye removal methods: a review, J. Environ. Chem. Eng. 6 (2018) 4676e4697, https://doi.org/10.1016/j.jece.2018.06.060. [5] M.T. Yagub, T.K. Sen, S. Afroze, H.M. Ang, Dye and its removal from aqueous solution by adsorption: a review, Adv. Colloid Interface Sci. 209 (2014), https://doi.org/10.1016/j.cis.2014.04.002. [6] M. Vakili, M. Rafatullah, B. Salamatinia, A.Z. Abdullah, M.H. Ibrahim, K.B. Tan, Z. Gholami, P. Amouzgar, Application of chitosan and its derivatives as adsorbents for dye removal from water and wastewater: a review, Carbohydr. Polym. 113 (2014) 115e130, https://doi.org/10.1016/j.carbpol.2014.07.007. [7] Y. Zhi-Yuan, Kinetics and mechanism of the adsorption of methylene blue onto ACFs, J. China Univ. Min. Technol. 18 (2008), https://doi.org/10.1016/ S1006-1266(08)60090-5, 0437e0440. [8] M. Rafatullah, O. Sulaiman, R. Hashim, A. Ahmad, Adsorption of methylene blue on low-cost adsorbents: a review, J. Hazard. Mater. 177 (2010) 70e80, https://doi.org/10.1016/j.jhazmat.2009.12.047. [9] M.A.M. Salleh, D.K. Mahmoud, W.A.W.A. Karim, A. Idris, Cationic and anionic dye adsorption by agricultural solid wastes: a comprehensive review, Desalination 280 (2011) 1e13, https://doi.org/10.1016/j.desal.2011.07.019. €z, T. Tay, S. Ucar, M. Erdem, Activated carbons from waste biomass [10] S. Karago by sulfuric acid activation and their use on methylene blue adsorption, Bioresour. Technol. 99 (2008) 6214e6222, https://doi.org/10.1016/ j.biortech.2007.12.019. [11] M.U. Dural, L. Cavas, S.K. Papageorgiou, F.K. Katsaros, Methylene blue adsorption on activated carbon prepared from Posidonia oceanica (L.) dead leaves: kinetics and equilibrium studies, Chem. Eng. J. 168 (2011) 77e85, https://doi.org/10.1016/j.cej.2010.12.038. [12] A.L. Cazetta, A.M.M. Vargas, E.M. Nogami, M.H. Kunita, M.R. Guilherme, A.C. Martins, T.L. Silva, J.C.G. Moraes, V.C. Almeida, NaOH-activated carbon of high surface area produced from coconut shell: kinetics and equilibrium studies from the methylene blue adsorption, Chem. Eng. J. 174 (2011) 117e125, https://doi.org/10.1016/j.cej.2011.08.058. [13] M. Auta, B.H. Hameed, Optimized waste tea activated carbon for adsorption of Methylene Blue and Acid Blue 29 dyes using response surface methodology, Chem. Eng. J. 175 (2011) 233e243, https://doi.org/10.1016/ j.cej.2011.09.100. re, L. Reinert, N. Benderdouche, L. Duclaux, Prepa[14] M. Benadjemia, L. Millie ration, characterization and Methylene Blue adsorption of phosphoric acid activated carbons from globe artichoke leaves, Fuel Process. Technol. 92 (2011) 1203e1212, https://doi.org/10.1016/j.fuproc.2011.01.014. [15] K.Y. Foo, B.H. Hameed, Microwave assisted preparation of activated carbon from pomelo skin for the removal of anionic and cationic dyes, Chem. Eng. J. 173 (2011) 385e390, https://doi.org/10.1016/j.cej.2011.07.073. [16] K.Y. Foo, B.H. Hameed, Microwave-assisted preparation and adsorption performance of activated carbon from biodiesel industry solid reside : influence of operational parameters, Bioresour. Technol. 103 (2012) 398e404, https://doi.org/10.1016/j.biortech.2011.09.116. [17] K.Y. Foo, B.H. Hameed, Dynamic adsorption behavior of methylene blue onto oil palm shell granular activated carbon prepared by microwave heating, Chem. Eng. J. (2012), https://doi.org/10.1016/j.cej.2012.06.073. [18] K.Y. Foo, B.H. Hameed, Factors affecting the carbon yield and adsorption capability of the mangosteen peel activated carbon prepared by microwave assisted K 2 CO 3 activation, Chem. Eng. J. 180 (2012) 66e74, https://doi.org/ 10.1016/j.cej.2011.11.002.

[19] K.Y. Foo, B.H. Hameed, Coconut husk derived activated carbon via microwave induced activation : effects of activation agents , preparation parameters and adsorption performance, Chem. Eng. J. 184 (2012) 57e65, https://doi.org/ 10.1016/j.cej.2011.12.084. [20] K.Y. Foo, B.H. Hameed, Textural porosity , surface chemistry and adsorptive properties of durian shell derived activated carbon prepared by microwave assisted NaOH activation, Chem. Eng. J. 187 (2012) 53e62, https://doi.org/ 10.1016/j.cej.2012.01.079. [21] J. Yener, T. Kopac, G. Dogu, T. Dogu, Dynamic analysis of sorption of Methylene Blue dye on granular and powdered activated carbon, Chem. Eng. J. 144 (2008) 400e406, https://doi.org/10.1016/j.cej.2008.02.009. [22] K.Y. Foo, B.H. Hameed, Adsorption characteristics of industrial solid waste derived activated carbon prepared by microwave heating for methylene blue, Fuel Process. Technol. 99 (2012) 103e109, https://doi.org/10.1016/ j.fuproc.2012.01.031. [23] K.Y. Foo, B.H. Hameed, Preparation , characterization and evaluation of adsorptive properties of orange peel based activated carbon via microwave induced K 2 CO 3 activation, Bioresour. Technol. 104 (2012) 679e686, https://doi.org/10.1016/j.biortech.2011.10.005. [24] K.Y. Foo, B.H. Hameed, Mesoporous activated carbon from wood sawdust by K2CO3 activation using microwave heating, Bioresour. Technol. 111 (2012) 425e432, https://doi.org/10.1016/j.biortech.2012.01.141. [25] M.J. Ahmed, S.K. Dhedan, Equilibrium isotherms and kinetics modeling of methylene blue adsorption on agricultural wastes-based activated carbons, Fluid Phase Equilib. 317 (2012) 9e14, https://doi.org/10.1016/ j.fluid.2011.12.026. [26] K. Mahapatra, D.S. Ramteke, L.J. Paliwal, Production of activated carbon from sludge of food processing industry under controlled pyrolysis and its application for methylene blue removal, J. Anal. Appl. Pyrolysis 95 (2012) 79e86, https://doi.org/10.1016/j.jaap.2012.01.009. [27] K.-L. Chiu, D.H.L. Ng, Synthesis and characterization of cotton-made activated carbon fiber and its adsorption of methylene blue in water treatment, Biomass Bioenergy 46 (2012) 102e110, https://doi.org/10.1016/ j.biombioe.2012.09.023. ngeles Martín, A. Martín, Treatment of pollutants in waste[28] M. Berrios, M. a water: adsorption of methylene blue onto olive-based activated carbon, J. Ind. Eng. Chem. 18 (2012) 780e784, https://doi.org/10.1016/ j.jiec.2011.11.125. [29] Y. Li, Q. Du, T. Liu, X. Peng, J. Wang, J. Sun, Y. Wang, S. Wu, Z. Wang, Y. Xia, L. Xia, Comparative study of methylene blue dye adsorption onto activated carbon, graphene oxide, and carbon nanotubes, Chem. Eng. Res. Des. 91 (2013) 361e368, https://doi.org/10.1016/j.cherd.2012.07.007. [30] H. Cherifi, B. Fatiha, H. Salah, Kinetic studies on the adsorption of methylene blue onto vegetal fiber activated carbons, Appl. Surf. Sci. 282 (2013) 52e59, https://doi.org/10.1016/j.apsusc.2013.05.031. [31] M. Kumar, R. Tamilarasan, Modeling studies for the removal of methylene blue from aqueous solution using Acacia fumosa seed shell activated carbon, J. Environ. Chem. Eng. (2013), https://doi.org/10.1016/j.jece.2013.08.027. [32] A.A. Attia, B.S. Girgis, N.A. Fathy, Removal of methylene blue by carbons derived from peach stones by H3PO4 activation: batch and column studies, Dyes Pigments 76 (2008) 282e289, https://doi.org/10.1016/ j.dyepig.2006.08.039. [33] M. Ghaedi, A.M. Ghaedi, F. Abdi, M. Roosta, A. Vafaei, A. Asghari, Principal component analysis- adaptive neuro-fuzzy inference system modeling and genetic algorithm optimization of adsorption of methylene blue by activated carbon derived from Pistacia khinjuk, Ecotoxicol. Environ. Saf. 96 (2013) 110e117, https://doi.org/10.1016/j.ecoenv.2013.05.015. [34] O. Pezoti Jr., A.L. Cazetta, I.P.A.F. Souza, K.C. Bedin, A.C. Martins, T.L. Silva, V.C. Almeida, Adsorption studies of methylene blue onto ZnCl 2 -activated carbon produced from buriti shells (Mauritia flexuosa L.), J. Ind. Eng. Chem. 20 (2014) 4401e4407, https://doi.org/10.1016/j.jiec.2014.02.007. [35] M. Ghaedi, M. Danaei Ghazanfarkhani, S. Khodadoust, N. Sohrabi, M. Oftade, Acceleration of methylene blue adsorption onto activated carbon prepared from dross licorice by ultrasonic: equilibrium, kinetic and thermodynamic studies, J. Ind. Eng. Chem. 20 (2014) 2548e2560, https://doi.org/10.1016/ j.jiec.2013.10.039. [36] Y. Gokce, Z. Aktas, Nitric acid modification of activated carbon produced from waste tea and adsorption of methylene blue and phenol, Appl. Surf. Sci. 313 (2014) 352e359, https://doi.org/10.1016/j.apsusc.2014.05.214. [37] M.J. Ahmed, S.K. Theydan, Optimization of microwave preparation conditions for activated carbon from Albizia lebbeck seed pods for methylene blue dye adsorption, J. Anal. Appl. Pyrolysis 105 (2014) 199e208, https://doi.org/ 10.1016/j.jaap.2013.11.005. [38] D. Xin-hui, C. Srinivasakannan, L. Jin-sheng, Process optimization of thermal regeneration of spent coal based activated carbon using steam and application to methylene blue dye adsorption, J. Taiwan Inst. Chem. Eng. 45 (2014) 1618e1627, https://doi.org/10.1016/j.jtice.2013.10.019. [39] Z.A. AlOthman, M.A. Habila, R. Ali, A. Abdel Ghafar, M.S. El-din Hassouna, Valorization of two waste streams into activated carbon and studying its adsorption kinetics, equilibrium isotherms and thermodynamics for methylene blue removal, Arab. J. Chem. 7 (2014) 1148e1158, https://doi.org/ 10.1016/j.arabjc.2013.05.007. [40] V. Makrigianni, A. Giannakas, Y. Deligiannakis, I. Konstantinou, Adsorption of phenol and methylene blue from aqueous solutions by pyrolytic tire char:

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233

[41]

[42]

[43]

[44]

[45]

[46]

[47]

[48]

[49]

[50]

[51]

[52]

[53]

[54]

[55]

[56]

[57]

[58]

[59]

[60]

equilibrium and kinetic studies, J. Environ. Chem. Eng. 3 (2015) 574e582, https://doi.org/10.1016/j.jece.2015.01.006. M.A. Islam, A. Benhouria, M. Asif, B.H. Hameed, Methylene blue adsorption on factory-rejected tea activated carbon prepared by conjunction of hydrothermal carbonization and sodium hydroxide activation processes, J. Taiwan Inst. Chem. Eng. 52 (2015) 57e64, https://doi.org/10.1016/ j.jtice.2015.02.010. Z. Li, Z. Jia, T. Ni, S. Li, Adsorption of methylene blue on natural cotton based flexible carbon fiber aerogels activated by novel air-limited carbonization method, J. Mol. Liq. 242 (2017) 747e756, https://doi.org/10.1016/ j.molliq.2017.07.062. S. Altenor, B. Carene, E. Emmanuel, J. Lambert, J.J. Ehrhardt, S. Gaspard, Adsorption studies of methylene blue and phenol onto vetiver roots activated carbon prepared by chemical activation, J. Hazard. Mater. 165 (2009) 1029e1039, https://doi.org/10.1016/j.jhazmat.2008.10.133. F. Marrakchi, M.J. Ahmed, W.A. Khanday, M. Asif, B.H. Hameed, Mesoporous-activated carbon prepared from chitosan flakes via single-step sodium hydroxide activation for the adsorption of methylene blue, Int. J. Biol. Macromol. 98 (2017), https://doi.org/10.1016/ j.ijbiomac.2017.01.119. M.A. Islam, M.J. Ahmed, W.A. Khanday, M. Asif, B.H. Hameed, Mesoporous activated coconut shell-derived hydrochar prepared via hydrothermal carbonization-NaOH activation for methylene blue adsorption, J. Environ. Manag. 203 (2017) 237e244, https://doi.org/10.1016/ j.jenvman.2017.07.029. M.A. Islam, M.J. Ahmed, W.A. Khanday, M. Asif, B.H. Hameed, Mesoporous activated carbon prepared from NaOH activation of rattan (Lacosperma secundiflorum) hydrochar for methylene blue removal, Ecotoxicol. Environ. Saf. 138 (2017), https://doi.org/10.1016/j.ecoenv.2017.01.010. M.A. Islam, S. Sabar, A. Benhouria, W.A. Khanday, M. Asif, B.H. Hameed, Nanoporous activated carbon prepared from karanj (Pongamia pinnata) fruit hulls for methylene blue adsorption, J. Taiwan Inst. Chem. Eng. 74 (2017) 96e104, https://doi.org/10.1016/j.jtice.2017.01.016. V. Tharaneedhar, P. Senthil Kumar, A. Saravanan, C. Ravikumar, V. Jaikumar, Prediction and interpretation of adsorption parameters for the sequestration of methylene blue dye from aqueous solution using microwave assisted corncob activated carbon, Sustain. Mater. Technol. 11 (2017) 1e11, https:// doi.org/10.1016/j.susmat.2016.11.001. D. Pathania, S. Sharma, P. Singh, Removal of methylene blue by adsorption onto activated carbon developed from Ficus carica bast, Arab. J. Chem. 10 (2017) S1445eS1451, https://doi.org/10.1016/j.arabjc.2013.04.021. M. Danish, T. Ahmad, R. Hashim, N. Said, M.N. Akhtar, J. Mohamad-Saleh, O. Sulaiman, Comparison of surface properties of wood biomass activated carbons and their application against rhodamine B and methylene blue dye, Surfaces and Interfaces 11 (2018) 1e13, https://doi.org/10.1016/ j.surfin.2018.02.001. Z. Heidarinejad, O. Rahmanian, M. Fazlzadeh, M. Heidari, Enhancement of methylene blue adsorption onto activated carbon prepared from Date Press Cake by low frequency ultrasound, J. Mol. Liq. 264 (2018) 591e599, https:// doi.org/10.1016/j.molliq.2018.05.100. A.M.M. Vargas, A.L. Cazetta, M.H. Kunita, T.L. Silva, V.C. Almeida, Adsorption of methylene blue on activated carbon produced from flamboyant pods (Delonix regia): study of adsorption isotherms and kinetic models, Chem. Eng. J. 168 (2011), https://doi.org/10.1016/j.cej.2011.01.067. K.Y. Foo, B.H. Hameed, A rapid regeneration of methylene blue dye-loaded activated carbons with microwave heating, J. Anal. Appl. Pyrolysis 98 (2012) 123e128, https://doi.org/10.1016/j.jaap.2012.07.006. H. Deng, L. Yang, G. Tao, J. Dai, Preparation and characterization of activated carbon from cotton stalk by microwave assisted chemical activationApplication in methylene blue adsorption from aqueous solution, J. Hazard. Mater. 166 (2009) 1514e1521, https://doi.org/10.1016/ j.jhazmat.2008.12.080. A. Reffas, V. Bernardet, B. David, L. Reinert, M.B. Lehocine, M. Dubois, N. Batisse, L. Duclaux, Carbons prepared from coffee grounds by H3PO4 activation: characterization and adsorption of methylene blue and Nylosan Red N-2RBL, J. Hazard. Mater. 175 (2010) 779e788, https://doi.org/10.1016/ j.jhazmat.2009.10.076. S.S. Ashour, Kinetic and equilibrium adsorption of methylene blue and remazol dyes onto steam-activated carbons developed from date pits, J. Saudi Chem. Soc. 14 (2010) 47e53, https://doi.org/10.1016/ j.jscs.2009.12.008. Q.-S. Liu, T. Zheng, N. Li, P. Wang, G. Abulikemu, Modification of bamboobased activated carbon using microwave radiation and its effects on the adsorption of methylene blue, Appl. Surf. Sci. 256 (2010) 3309e3315, https:// doi.org/10.1016/j.apsusc.2009.12.025. M.M. El-Halwany, Study of adsorption isotherms and kinetic models for Methylene Blue adsorption on activated carbon developed from Egyptian rice hull (Part II), Desalination 250 (2010) 208e213, https://doi.org/10.1016/ j.desal.2008.07.030. L. Sun, S. Wan, W. Luo, Biochars prepared from anaerobic digestion residue, palm bark, and eucalyptus for adsorption of cationic methylene blue dye: characterization, equilibrium, and kinetic studies, Bioresour. Technol. 140 (2013) 406e413, https://doi.org/10.1016/j.biortech.2013.04.116. S. Liu, J. Li, S. Xu, M. Wang, Y. Zhang, X. Xue, A modified method for enhancing adsorption capability of banana pseudostem biochar towards

[61]

[62]

[63]

[64]

[65]

[66]

[67]

[68]

[69]

[70]

[71]

[72]

[73]

[74]

[75]

[76]

[77]

[78]

[79]

[80]

[81]

19

methylene blue at low temperature, Bioresour. Technol. 282 (2019) 48e55, https://doi.org/10.1016/j.biortech.2019.02.092. B. Ji, J. Wang, H. Song, W. Chen, Removal of methylene blue from aqueous solutions using biochar derived from a fallen leaf by slow pyrolysis : behavior and mechanism, J. Environ. Chem. Eng. 7 (2019), https://doi.org/ 10.1016/j.jece.2019.103036, 103036. Y. Wang, Y. Zhang, S. Li, W. Zhong, W. Wei, Enhanced methylene blue adsorption onto activated reed-derived biochar by tannic acid, J. Mol. Liq. 268 (2018) 658e666, https://doi.org/10.1016/j.molliq.2018.07.085. D. Angela, G. Sumalinog, S.C. Capareda, M. Daniel, G. De Luna, Evaluation of the effectiveness and mechanisms of acetaminophen and methylene blue dye adsorption on activated biochar derived from municipal solid wastes, J. Environ. Manag. 210 (2018) 255e262, https://doi.org/10.1016/ j.jenvman.2018.01.010. W. Que, L. Jiang, C. Wang, Y. Liu, Z. Zeng, X. Wang, Q. Ning, S. Liu, P. Zhang, S. Liu, Influence of sodium dodecyl sulfate coating on adsorption of methylene blue by biochar from aqueous solution, J. Environ. Sci. 70 (2017) 166e174, https://doi.org/10.1016/j.jes.2017.11.027. G. Akkaya, F. Güzel, H. Say, Optimal oxidation with nitric acid of biochar derived from pyrolysis of weeds and its application in removal of hazardous dye methylene blue from aqueous solution, J. Clean. Prod. 144 (2017) 260e265, https://doi.org/10.1016/j.jclepro.2017.01.029. S. Fan, Y. Wang, Z. Wang, J. Tang, J. Tang, X. Li, Removal of methylene blue from aqueous solution by sewage sludge-derived biochar : adsorption kinetics , equilibrium , thermodynamics and mechanism, Biochem. Pharmacol. 5 (2017) 601e611, https://doi.org/10.1016/j.jece.2016.12.019. L. Borah, M. Goswami, P. Phukan, Adsorption of methylene blue and eosin yellow using porous carbon prepared from tea waste: adsorption equilibrium, kinetics and thermodynamics study, J. Environ. Chem. Eng. 3 (2015) 1018e1028, https://doi.org/10.1016/j.jece.2015.02.013. M. Ghaedi, S.N. Kokhdan, Removal of methylene blue from aqueous solution by wood millet carbon optimization using response surface methodology, Spectrochim. Acta Part A Mol. Biomol. Spectrosc. 136 (2015) 141e148, https://doi.org/10.1016/j.saa.2014.07.048. W. Zhang, L.Y. Zhang, X.J. Zhao, Z. Zhou, Citrus pectin derived porous carbons as a superior adsorbent toward removal of methylene blue, J. Solid State Chem. 243 (2016) 101e105, https://doi.org/10.1016/j.jssc.2016.08.014. L. Lonappan, T. Rouissi, R.K. Das, S.K. Brar, A.A. Ramirez, M. Verma, R.Y. Surampalli, J.R. Valero, Adsorption of methylene blue on biochar microparticles derived from different waste materials, Waste Manag. (2016), https://doi.org/10.1016/j.wasman.2016.01.015. F. Marrakchi, M. Auta, W.A. Khanday, B.H. Hameed, High-surface-area and nitrogen-rich mesoporous carbon material from fishery waste for effective adsorption of methylene blue, Powder Technol. 321 (2017) 428e434, https:// doi.org/10.1016/j.powtec.2017.08.023. A. Ronix, O. Pezoti, L.S. Souza, I.P.A.F. Souza, K.C. Bedin, P.S.C. Souza, T.L. Silva, S.A.R. Melo, A.L. Cazetta, V.C. Almeida, Hydrothermal carbonization of coffee husk: optimization of experimental parameters and adsorption of methylene blue dye, J. Environ. Chem. Eng. 5 (2017) 4841e4849, https://doi.org/ 10.1016/j.jece.2017.08.035. Z. Li, G. Wang, K. Zhai, C. He, Q. Li, P. Guo, Methylene blue adsorption from aqueous solution by loofah sponge-based porous carbons, Colloids Surf., A 538 (2018) 28e35, https://doi.org/10.1016/j.colsurfa.2017.10.046. M.J. Ahmed, P.U. Okoye, E.H. Hummadi, B.H. Hameed, High-performance porous biochar from the pyrolysis of natural and renewable seaweed ( Gelidiella acerosa ) and its application for the adsorption of methylene blue, Bioresour. Technol. 278 (2019) 159e164, https://doi.org/10.1016/ j.biortech.2019.01.054. L. Wang, Z. Huang, M. Zhang, B. Chai, Adsorption of methylene blue from aqueous solution on modified ACFs by chemical vapor deposition, Chem. Eng. J. 189e190 (2012) 168e174, https://doi.org/10.1016/j.cej.2012.02.049. M. Ghaedi, S. Heidarpour, S. Nasiri Kokhdan, R. Sahraie, A. Daneshfar, B. Brazesh, Comparison of silver and palladium nanoparticles loaded on activated carbon for efficient removal of Methylene blue: kinetic and isotherm study of removal process, Powder Technol. (2012), https://doi.org/ 10.1016/j.powtec.2012.04.030. A. Asfaram, M. Ghaedi, S. Hajati, A. Goudarzi, A. Akbar, Simultaneous ultrasound-assisted ternary adsorption of dyes onto copper-doped zinc sulfide nanoparticles loaded on activated carbon : optimization by response surface methodology, Spectrochim. Acta Part A Mol. Biomol. Spectrosc. 145 (2015) 203e212, https://doi.org/10.1016/j.saa.2015.03.006. E.I. El-Shafey, S.N.F. Ali, S. Al-Busafi, H.A.J. Al-Lawati, Preparation and characterization of surface functionalized activated carbons from date palm leaflets and application for methylene blue removal, J. Environ. Chem. Eng. 4 (2016) 2713e2724, https://doi.org/10.1016/j.jece.2016.05.015. S. Ye, W. Jin, Q. Huang, Y. Hu, Y. Li, B. Li, KGM-based magnetic carbon aerogels matrix for the uptake of methylene blue and methyl orange, Int. J. Biol. Macromol. 92 (2016) 1169e1174, https://doi.org/10.1016/ j.ijbiomac.2016.07.106. F. Nekouei, H. Kargarzadeh, S. Nekouei, F. Keshtpour, A.S.H. Makhlouf, Novel, facile, and fast technique for synthesis of AgCl nanorods loaded on activated carbon for removal of methylene blue dye, Process Saf. Environ. Prot. 103 (2016) 212e226, https://doi.org/10.1016/j.psep.2016.07.010. H. Mazaheri, M. Ghaedi, A. Asfaram, S. Hajati, Performance of CuS nanoparticle loaded on activated carbon in the adsorption of methylene blue and

20

[82]

[83]

[84]

[85]

[86]

[87]

[88]

[89]

[90]

[91]

[92]

[93]

[94]

[95]

[96]

[97]

[98]

[99]

[100]

[101]

[102]

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233 bromophenol blue dyes in binary aqueous solutions: using ultrasound power and optimization by central composite design, J. Mol. Liq. 219 (2016) 667e676, https://doi.org/10.1016/j.molliq.2016.03.050. F. Marrakchi, M. Bouaziz, B.H. Hameed, Activated carboneclay composite as an effective adsorbent from the spent bleaching sorbent of olive pomace oil: process optimization and adsorption of acid blue 29 and methylene blue, Chem. Eng. Res. Des. 128 (2017) 221e230, https://doi.org/10.1016/ j.cherd.2017.10.015. P. Liao, Z. Malik, W. Zhang, S. Yuan, M. Tong, K. Wang, Adsorption of dyes from aqueous solutions by microwave modified bamboo charcoal, Chem. Eng. J. 195e196 (2012) 339e346, https://doi.org/10.1016/j.cej.2012.04.092. D. shen Tong, C.W. Wu, M.O. Adebajo, G.C. Jin, W.H. Yu, S.F. Ji, C.H. Zhou, Adsorption of methylene blue from aqueous solution onto porous cellulosederived carbon/montmorillonite nanocomposites, Appl. Clay Sci. 161 (2018) 256e264, https://doi.org/10.1016/j.clay.2018.02.017. L. Meili, P. V Lins, C.L.P.S. Zanta, J.I. Soletti, L.M.O. Ribeiro, C.B. Dornelas, T.L. Silva, M.G.A. Vieira, MgAl-LDH/Biochar composites for methylene blue removal by adsorption, Appl. Clay Sci. 168 (2019) 11e20, https://doi.org/ 10.1016/j.clay.2018.10.012. Y. Li, Y. Zhang, Y. Zhang, G. Wang, S. Li, R. Han, W. Wei, Reed biochar supported hydroxyapatite nanocomposite : characterization and reactivity for methylene blue removal from aqueous media, J. Mol. Liq. 263 (2018) 53e63, https://doi.org/10.1016/j.molliq.2018.04.132. M. Ghaedi, M. Pakniat, Z. Mahmoudi, S. Hajati, R. Sahraei, A. Daneshfar, Synthesis of nickel sulfide nanoparticles loaded on activated carbon as a novel adsorbent for the competitive removal of Methylene blue and Safranin-O, Spectrochim. Acta Part A Mol. Biomol. Spectrosc. 123 (2014) 402e409, https://doi.org/10.1016/j.saa.2013.12.083. X. Li, Preparation and adsorption properties of biochar/g-C3N4 composites for methylene blue in aqueous solution, Hindawi J. Nanomater. J. Nanomater. (2019), https://doi.org/10.1155/2019/2394184, 2019. M. Ghaedi, A.M. Ghaedi, M. Hossainpour, A. Ansari, M.H. Habibi, A.R. Asghari, Least square-support vector (LS-SVM) method for modeling of methylene blue dye adsorption using copper oxide loaded on activated carbon: kinetic and isotherm study, J. Ind. Eng. Chem. 20 (2014) 1641e1649, https://doi.org/ 10.1016/j.jiec.2013.08.011. A.F. Hassan, A.M. Abdel-Mohsen, M.M.G. Fouda, Comparative study of calcium alginate, activated carbon, and their composite beads on methylene blue adsorption, Carbohydr. Polym. 102 (2014) 192e198, https://doi.org/ 10.1016/j.carbpol.2013.10.104. M. Roosta, M. Ghaedi, A. Daneshfar, R. Sahraei, A. Asghari, Optimization of the ultrasonic assisted removal of methylene blue by gold nanoparticles loaded on activated carbon using experimental design methodology, Ultrason. Sonochem. 21 (2014) 242e252, https://doi.org/10.1016/ j.ultsonch.2013.05.014. X. Zhang, L. Cheng, X. Wu, Y. Tang, Y. Wu, Activated carbon coated palygorskite as adsorbent by activation and its adsorption for methylene blue, J. Environ. Sci. 33 (2015) 97e105, https://doi.org/10.1016/j.jes.2015.01.014. X.P. Wu, Y.Q. Xu, X.L. Zhang, Y.C. Wu, P. Gao, Adsorption of lowconcentration methylene blue onto a palygorskite/carbon composite, Xinxing Tan Cailiao/New Carbon Mater. 30 (2015) 71e78, https://doi.org/ 10.1016/S1872-5805(15)60176-7. A. Benhouria, M.A. Islam, H. Zaghouane-Boudiaf, M. Boutahala, B.H. Hameed, Calcium alginate-bentonite-activated carbon composite beads as highly effective adsorbent for methylene blue, Chem. Eng. J. 270 (2015) 621e630, https://doi.org/10.1016/j.cej.2015.02.030. A. Asfaram, M. Ghaedi, S. Hajati, M. Rezaeinejad, A. Goudarzi, M.K. Purkait, Rapid removal of Auramine-O and Methylene blue by ZnS: Cu nanoparticles loaded on activated carbon: a response surface methodology approach, J. Taiwan Inst. Chem. Eng. 53 (2015) 80e91, https://doi.org/10.1016/ j.jtice.2015.02.026. H. Wang, H. Gao, M. Chen, X. Xu, X. Wang, C. Pan, J. Gao, Microwave-assisted synthesis of reduced graphene oxide/titania nanocomposites as an adsorbent for methylene blue adsorption, Appl. Surf. Sci. 360 (2016) 840e848, https:// doi.org/10.1016/j.apsusc.2015.11.075. € r, Synthesis of graphene oxide/magnesium oxide M. Heidarizad, S.S. S¸engo nanocomposites with high-rate adsorption of methylene blue, J. Mol. Liq. 224 (2016) 607e617, https://doi.org/10.1016/j.molliq.2016.09.049. P. Zhang, D.O. Connor, Y. Wang, L. Jiang, T. Xia, L. Wang, D.C.W. Tsang, Y. Sik, D. Hou, A green biochar/iron oxide composite for methylene blue removal, J. Hazard Mater. 384 (2020), https://doi.org/10.1016/j.jhazmat.2019.121286, 121286. Q. Gan, W. Shi, Y. Xing, Y. Hou, A polyoxoniobate/g-C3N4 nanoporous material with high adsorption capacity of methylene blue from aqueous solution, Front. Chem. 6 (2018) 1e10, https://doi.org/10.3389/fchem.2018.00007. M. Zhao, P. Liu, Adsorption of methylene blue from aqueous solutions by modified expanded graphite powder, Desalination 249 (2009) 331e336, https://doi.org/10.1016/j.desal.2009.01.037. T. Liu, Y. Li, Q. Du, J. Sun, Y. Jiao, G. Yang, Z. Wang, Y. Xia, W. Zhang, K. Wang, H. Zhu, D. Wu, Adsorption of methylene blue from aqueous solution by graphene, Colloids Surfaces B Biointerfaces 90 (2012) 197e203, https:// doi.org/10.1016/j.colsurfb.2011.10.019. L. Ai, J. Jiang, Removal of methylene blue from aqueous solution with selfassembled cylindrical graphene-carbon nanotube hybrid, Chem. Eng. J. 192 (2012) 156e163, https://doi.org/10.1016/j.cej.2012.03.056.

[103] P. Wang, M. Cao, C. Wang, Y. Ao, J. Hou, J. Qian, Kinetics and thermodynamics of adsorption of methylene blue by a magnetic graphene-carbon nanotube composite, Appl. Surf. Sci. 290 (2014) 116e124, https://doi.org/10.1016/ j.apsusc.2013.11.010. [104] M. Ghaedi, N. Zeinali, A.M. Ghaedi, M. Teimuori, J. Tashkhourian, Artificial neural network-genetic algorithm based optimization for the adsorption of methylene blue and brilliant green from aqueous solution by graphite oxide nanoparticle, Spectrochim. Acta Part A Mol. Biomol. Spectrosc. 125 (2014) 264e277, https://doi.org/10.1016/j.saa.2013.12.082. [105] H. Yan, X. Tao, Z. Yang, K. Li, H. Yang, A. Li, R. Cheng, Effects of the oxidation degree of graphene oxide on the adsorption of methylene blue, J. Hazard. Mater. 268 (2014) 191e198, https://doi.org/10.1016/j.jhazmat.2014.01.015. [106] D.K. Padhi, K.M. Parida, S.K. Singh, Mechanistic aspects of enhanced Congo red adsorption over graphene oxide in presence of methylene blue, J. Environ. Chem. Eng. 4 (2016) 3498e3511, https://doi.org/10.1016/ j.jece.2016.07.011. [107] C. Yan, C. Wang, J. Yao, L. Zhang, X. Liu, Adsorption of methylene blue on mesoporous carbons prepared using acid- and alkaline-treated zeolite X as the template, Colloids Surfaces A Physicochem. Eng. Asp. 333 (2009) 115e119, https://doi.org/10.1016/j.colsurfa.2008.09.028. [108] A. Derylo-Marczewska, A.W. Marczewski, S. Winter, D. Sternik, Studies of adsorption equilibria and kinetics in the systems : aqueous solution of dyes e mesoporous carbons, Appl. Surf. Sci. 256 (2010) 5164e5170, https:// doi.org/10.1016/j.apsusc.2009.12.085. [109] Q. Jin, Y. Li, D. Yang, J. Cui, Chitosan-derived three-dimensional porous carbon for fast removal of methylene blue from wastewater, RSC Adv. 8 (2018) 1255e1264, https://doi.org/10.1039/C7RA11770A. [110] A.W. Marczewski, Application of mixed order rate equations to adsorption of methylene blue on mesoporous carbons, Appl. Surf. Sci. 256 (2010) 5145e5152, https://doi.org/10.1016/j.apsusc.2009.12.078. [111] Z. Jia, Z. Li, S. Li, Y. Li, R. Zhu, Adsorption performance and mechanism of methylene blue on chemically activated carbon spheres derived from hydrothermally-prepared poly(vinyl alcohol) microspheres, J. Mol. Liq. 220 (2016) 56e62, https://doi.org/10.1016/j.molliq.2016.04.063. [112] E.A.N. Simonetti, L. de S. Cividanes, T.M.B. Campos, B.R.C. de Menezes, F.S. Brito, G.P. Thim, Carbon and TiO2 synergistic effect on methylene blue adsorption, Mater. Chem. Phys. 177 (2016) 330e338, https://doi.org/ 10.1016/j.matchemphys.2016.04.035. [113] K.C. Bedin, A.C. Martins, A.L. Cazetta, O. Pezoti, V.C. Almeida, KOH-activated carbon prepared from sucrose spherical carbon: adsorption equilibrium, kinetic and thermodynamic studies for Methylene Blue removal, Chem. Eng. J. 286 (2016) 476e484, https://doi.org/10.1016/j.cej.2015.10.099. [114] O. Kazak, Y.R. Eker, I. Akin, H. Bingol, A. Tor, A novel red mud@sucrose based carbon composite: preparation, characterization and its adsorption performance toward methylene blue in aqueous solution, J. Environ. Chem. Eng. 5 (2017) 2639e2647, https://doi.org/10.1016/j.jece.2017.05.018. [115] A.A. Narvekar, J.B. Fernandes, S.G. Tilve, Adsorption behavior of methylene blue on glycerol based carbon materials, J. Environ. Chem. Eng. 6 (2018) 1714e1725, https://doi.org/10.1016/j.jece.2018.02.016. [116] Q. Zhou, X. Jiang, Y. Guo, G. Zhang, W. Jiang, An ultra-high surface area mesoporous carbon prepared by a novel MnO-templated method for highly effective adsorption of methylene blue, Chemosphere 201 (2018) 519e529, https://doi.org/10.1016/j.chemosphere.2018.03.045. [117] B. Chen, Z. Yang, G. Ma, D. Kong, W. Xiong, J. Wang, Y. Zhu, Y. Xia, Heteroatom-doped porous carbons with enhanced carbon dioxide uptake and excellent methylene blue adsorption capacities, Microporous Mesoporous Mater. 257 (2018) 1e8, https://doi.org/10.1016/j.micromeso.2017.08.026. [118] Y. Yao, F. Xu, M. Chen, Z. Xu, Z. Zhu, Adsorption behavior of methylene blue on carbon nanotubes, Bioresour. Technol. 101 (2010) 3040e3046, https:// doi.org/10.1016/j.biortech.2009.12.042. [119] C. Deng, J. Liu, W. Zhou, Y.K. Zhang, K.F. Du, Z.M. Zhao, Fabrication of spherical cellulose/carbon tubes hybrid adsorbent anchored with welan gum polysaccharide and its potential in adsorbing methylene blue, Chem. Eng. J. 200e202 (2012) 452e458, https://doi.org/10.1016/j.cej.2012.06.059. [120] Z. Zhang, X. Xu, Wrapping carbon nanotubes with poly (sodium 4styrenesulfonate) for enhanced adsorption of methylene blue and its mechanism, Chem. Eng. J. 256 (2014) 85e92, https://doi.org/10.1016/ j.cej.2014.06.020. [121] J. Gong, J. Liu, Z. Jiang, X. Wen, E. Mijowska, T. Tang, X. Chen, A facile approach to prepare porous cup-stacked carbon nanotube with high performance in adsorption of methylene blue, J. Colloid Interface Sci. 445 (2015) 195e204, https://doi.org/10.1016/j.jcis.2014.12.078. [122] D. Robati, B. Mirza, R. Ghazisaeidi, M. Rajabi, O. Moradi, I. Tyagi, S. Agarwal, V.K. Gupta, Adsorption behavior of methylene blue dye on nanocomposite multi-walled carbon nanotube functionalized thiol (MWCNT-SH) as new adsorbent, J. Mol. Liq. 216 (2016) 830e835, https://doi.org/10.1016/ j.molliq.2016.02.004. [123] M. Manilo, N. Lebovka, S. Barany, Mechanism of Methylene Blue adsorption on hybrid laponite-multi-walled carbon nanotube particles, J. Environ. Sci. (China) 42 (2016) 134e141, https://doi.org/10.1016/j.jes.2015.06.011. [124] O. Duman, S. Tunç, T.G. Polat, B.K.I. Bozoǧlan, Synthesis of magnetic oxidized multiwalled carbon nanotube-k-carrageenan-Fe3O4nanocomposite adsorbent and its application in cationic Methylene Blue dye adsorption, Carbohydr. Polym. 147 (2016) 79e88, https://doi.org/10.1016/ j.carbpol.2016.03.099.

E. Santoso et al. / Materials Today Chemistry 16 (2020) 100233 [125] B. Wang, B. Gao, A.R. Zimmerman, X. Lee, Impregnation of multiwall carbon nanotubes in alginate beads dramatically enhances their adsorptive ability to aqueous methylene blue, Chem. Eng. Res. Des. 1 (2018) 235e242, https:// doi.org/10.1016/j.cherd.2018.03.026. [126] J.T. Li, B.L. Li, H.C. Wang, X.B. Bian, X.M. Wang, A wormhole-structured mesoporous carbon with superior adsorption for dyes, Carbon NY 49 (2011) 1912e1918, https://doi.org/10.1016/j.carbon.2011.01.016. [127] Y. Gao, S. Xu, Q. Yue, Y. Wu, B. Gao, Chemical preparation of crab shell-based activated carbon with superior adsorption performance for dye removal from wastewater, J. Taiwan Inst. Chem. Eng. 61 (2016) 327e335, https:// doi.org/10.1016/j.jtice.2015.12.023. [128] L. Ai, C. Zhang, F. Liao, Y. Wang, M. Li, L. Meng, J. Jiang, Removal of methylene blue from aqueous solution with magnetite loaded multi-wall carbon nanotube: kinetic, isotherm and mechanism analysis, J. Hazard. Mater. (2011), https://doi.org/10.1016/j.jhazmat.2011.10.041. [129] H. Karaer, I. Kaya, Synthesis, characterization of magnetic chitosan/active charcoal composite and using at the adsorption of methylene blue and reactive blue4, Microporous Mesoporous Mater. 232 (2016) 26e38, https:// doi.org/10.1016/j.micromeso.2016.06.006. €hler, T.D. Bucheli, Activated carbon [130] N. Hagemann, K.S. Id, H. Schmidt, M.A. Bo , biochar and Charcoal : linkages and synergies across pyrogenic carbon ’ s ABC s, Water 10 (2018) 182, https://doi.org/10.3390/w10020182. [131] A.M.M. Vargas, C.A. Garcia, E.M. Reis, E. Lenzi, W.F. Costa, V.C. Almeida, NaOH-activated carbon from flamboyant ( Delonix regia ) pods : optimization of preparation conditions using central composite rotatable design, Chem. Eng. J. 162 (2010) 43e50, https://doi.org/10.1016/j.cej.2010.04.052. €, Capture of Co ( II ) [132] E. Repo, L. Malinen, R. Koivula, R. Harjula, M. Sillanp€ aa from its aqueous EDTA-chelate by DTPA-modified silica gel and chitosan, J. Hazard. Mater. 187 (2011) 122e132, https://doi.org/10.1016/ j.jhazmat.2010.12.113. _ Tosun, Ammonium Removal from Aqueous Solutions by Clinoptilolite: [133] I. Determination of Isotherm and Thermodynamic Parameters and Comparison of Kinetics by the Double Exponential Model and Conventional Kinetic Models, 2012, pp. 970e984, https://doi.org/10.3390/ijerph9030970. [134] K.V. Kumar, M.M. de Castro, M. Martinez-Escandell, M. Molina-Sabio, F. Rodriguez-Reinoso, A site energy distribution function from Toth isotherm for adsorption of gases on heterogeneous surfaces w, Phys. Chem. Chem. Phys. (2011) 5753e5759, https://doi.org/10.1039/c0cp00902d. [135] M. Ghaedi, A. Golestani Nasab, S. Khodadoust, M. Rajabi, S. Azizian, Application of activated carbon as adsorbents for efficient removal of methylene blue: kinetics and equilibrium study, J. Ind. Eng. Chem. 20 (2014) 2317e2324, https://doi.org/10.1016/j.jiec.2013.10.007. [136] C.A. Bas, Applicability of the various adsorption models of three dyes adsorption onto activated carbon prepared waste apricot, J. Hazard. Mater. 135 (2006) 232e241, https://doi.org/10.1016/j.jhazmat.2005.11.055. [137] S.K. Milonjik, A consideration of the correct calculation of thermodynamic parameters of adsorption, J. Serb. Chem. Soc. 72 (2007) 1363e1367, https:// doi.org/10.2298/JSC0712363M. [138] Y. Liu, Is the Free Energy Change of Adsorption Correctly Calculated ?, 2009, pp. 1981e1985. [139] C. Kuo, C. Wu, J. Wu, Journal of Colloid and Interface Science Adsorption of direct dyes from aqueous solutions by carbon nanotubes : determination of equilibrium , kinetics and thermodynamics parameters, J. Colloid Interface Sci. 327 (2008) 308e315, https://doi.org/10.1016/j.jcis.2008.08.038. [140] R.L. Liu, Y. Liu, X.Y. Zhou, Z.Q. Zhang, J. Zhang, F.Q. Dang, Biomass-derived highly porous functional carbon fabricated by using a free-standing template for efficient removal of methylene blue, Bioresour. Technol. (2014), https:// doi.org/10.1016/j.biortech.2013.12.034. [141] K.-W. Jung, B.H. Choi, M.-J. Hwang, T.-U. Jeong, K.-H. Ahn, Fabrication of granular activated carbons derived from spent coffee grounds by entrapment in calcium alginate beads for adsorption of acid orange 7 and

[142]

[143]

[144]

[145]

[146]

[147]

[148]

[149]

[150]

[151]

[152]

[153]

[154]

[155]

21

methylene blue, Bioresour. Technol. J. 219 (2016) 185e195, https://doi.org/ 10.1016/j.biortech.2016.07.098. H. Ge, C. Wang, S. Liu, Z. Huang, Synthesis of citric acid functionalized magnetic graphene oxide coated corn straw for methylene blue adsorption, Bioresour. Technol. (2016), https://doi.org/10.1016/j.biortech.2016.09.060.  ~o, I.P.A.F. Souza, O. Pezoti Junior, A.L. Cazetta, R.C. Gomes, E.O. Bariza A.C. Martins, T. Asefa, V.C. Almeida, Synthesis of ZnCl2-activated carbon from macadamia nut endocarp (Macadamia integrifolia) by microwave-assisted pyrolysis: optimization using RSM and methylene blue adsorption, J. Anal. Appl. Pyrolysis 105 (2014) 166e176, https://doi.org/10.1016/ j.jaap.2013.10.015. L. Shi, G. Zhang, D. Wei, T. Yan, X. Xue, S. Shi, Q. Wei, Preparation and utilization of anaerobic granular sludge-based biochar for the adsorption of methylene blue from aqueous solutions, J. Mol. Liq. 198 (2014) 334e340, https://doi.org/10.1016/j.molliq.2014.07.023. S. Fan, J. Tang, Y. Wang, H. Li, H. Zhang, J. Tang, Z. Wang, X. Li, Biochar prepared from co-pyrolysis of municipal sewage sludge and tea waste for the adsorption of methylene blue from aqueous solutions : kinetics , isotherm , thermodynamic and mechanism, J. Mol. Liq. 220 (2016) 432e441, https:// doi.org/10.1016/j.molliq.2016.04.107. Z. Ding, Y. Wan, X. Hu, S. Wang, A.R. Zimmerman, B. Gao, Sorption of lead and methylene blue onto hickory biochars from different pyrolysis temperatures : importance of physicochemical properties, J. Ind. Eng. Chem. 37 (2016) 261e267, https://doi.org/10.1016/j.jiec.2016.03.035. Y. Wang, R. Liu, Comparison of characteristics of twenty-one types of biochar and their ability to remove multi-heavy metals and methylene blue in solution, Fuel Process. Technol. 160 (2017) 55e63, https://doi.org/10.1016/ j.fuproc.2017.02.019. M. Fronczak, M. Krajewska, K. Demby, M. Bystrzejewski, Extraordinary adsorption of methyl blue onto sodium-doped graphitic carbon nitride, J. Phys. Chem. C 121 (2017) 15756e15766, https://doi.org/10.1021/ acs.jpcc.7b03674. N.H. Othman, N.H. Alias, M.Z. Shahruddin, N.F. Abu Bakar, N.R. Nik Him, W.J. Lau, Adsorption kinetics of methylene blue dyes onto magnetic graphene oxide, J. Environ. Chem. Eng. 6 (2018) 2803e2811, https://doi.org/ 10.1016/j.jece.2018.04.024. M.A. Franciski, E.C. Peres, M. Godinho, D. Perondi, E.L. Foletto, G.C. Collazzo, G.L. Dotto, Development of CO2 activated biochar from solid wastes of a beer industry and its application for methylene blue adsorption, Waste Manag. 78 (2018) 630e638, https://doi.org/10.1016/ j.wasman.2018.06.040. R.M. Novais, A.P.F. Caetano, M.P. Seabra, J.A. Labrincha, R.C. Pullar, Extremely fast and efficient methylene blue adsorption using eco-friendly cork and paper waste-based activated carbon adsorbents, J. Clean. Prod. 197 (2018) 1137e1147, https://doi.org/10.1016/j.jclepro.2018.06.278. A. Kumar, H.M. Jena, Removal of methylene blue and phenol onto prepared activated carbon from Fox nutshell by chemical activation in batch and fixed-bed column, J. Clean. Prod. 137 (2016) 1246e1259, https://doi.org/ 10.1016/j.jclepro.2016.07.177. N. Chaukura, E.C. Murimba, W. Gwenzi, Environmental Technology & Innovation Sorptive removal of methylene blue from simulated wastewater using biochars derived from pulp and paper sludge, Environ. Technol. Innov. 8 (2017) 132e140, https://doi.org/10.1016/j.eti.2017.06.004. B. Ren, Y. Xu, L. Zhang, Z. Liu, Carbon-doped graphitic carbon nitride as environment-benign adsorbent for methylene blue adsorption : kinetics , isotherm and thermodynamics study, J. Taiwan Inst. Chem. Eng. 88 (2018) 114e120, https://doi.org/10.1016/j.jtice.2018.03.041. € A. Murray, B. Ormeci, Competitive effects of humic acid and wastewater on adsorption of Methylene Blue dye by activated carbon and non-imprinted polymers, J. Environ. Sci. (China) (2018), https://doi.org/10.1016/ j.jes.2017.04.029.