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Potential application of chicken manure biochar towards toxic phenol and 2,4-dinitrophenol in wastewaters
Journal of Environmental Management 251 (2019) 109556
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Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman
Research article
Potential application of chicken manure biochar towards toxic phenol and 2, 4-dinitrophenol in wastewaters
T
Phan Quang Thanga,b, Kim Jitaec,∗∗, Bach Long Giangd,e, N.M. Vietc, Pham Thi Huongc,∗ a
Division of Computational Mathematics and Engineering, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam Faculty of Environment & Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Vietnam c Center for Advanced Chemistry, Institute of Research and Development, Duy Tan University, Da Nang, Vietnam d NTT Hi-Tech Institute, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh Street, Dist. 4, Ho Chi Minh City, Vietnam e Center of Excellence for Green Energy and Environmental Nanomaterials, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam b
ARTICLE INFO
ABSTRACT
Keywords: Adsorption Biochar Chicken manure Phenol 2,4-Dinitrophenol Mechanism
In this study, chicken manure biochar (CBC) was prepared and applied as adsorbent for the removal of phenolic pollutants including phenol (Ph) and 2,4-Dinitrophenol (DNP) from wastewaters. The feasibility analysis was focused on the adsorption effects of various factors, such as initial concentration, adsorbent dosage and reaction time. The results showed that BC could efficiently remove the Ph and DNP within 90 min of reaction time. Increasing of CBC dosage up to 0.3 g results in the maximum removal efficiency of Ph and DNP and lowers initial concentration which is beneficial for the adsorption of phenolic compounds. The second-order kinetic model and the Langmuir isotherm provided the best correlation with the adsorption data. Based on the Langmuir isotherm, maximum adsorption capacities (qmax) of Ph and DNP were found at 106.2 and 148.1 mg g−1, respectively. The obtained qmax values for CB were higher than those reported in literature on the adsorption of Ph and DNP using different biochar. Analyzing the regeneration characteristics, BC displayed high reusability with less than 20% loss in adsorption capacities of Ph and DNP, even after five repeated cycles. Investigation of the adsorption equilibrium under various conditions suggested several possible interaction mechanisms, including hydrogen bonding, electrostatic interaction and π- π bonding, which were attributed to the binding affinity of the adsorbent-adsorbate interaction. In the field application, the CBC showed an excellent removal efficiencies of Ph and DNP from industrial wastewaters (around 80% phenolic pollutants were removed). These findings support the potential use of CBC as effective adsorbent for treatment of wastewater containing Ph and DNP.
1. Introduction Environmental pollution is becoming a global issue with the rapid development of industrialization (Rene et al., 2018a, 2018b; Uddandarao et al., 2019; Vinati et al., 2019). Phenolic compounds such as phenol and 2,4-Dinitrophenol are common constituent of industrial wastewater produced from petroleum refineries, coal gasification plants, phenolic resin industries, pesticides, dyes, plastics manufacture and pharmaceutical industries. Phenol and 2,4-Dinitrophenol are recognized as emerging contaminants because of their high toxicity, high resistance to biodegradation and carcinogenicity properties even at low concentrations (She et al., 2005; Das et al., 2015; Pan et al., 2016; Pham et al., 2016a, 2016b; Tang et al., 2018). Exposure to phenol may result
in systemic poisoning, weakness, sweating, headache, shock, excitement, kidney damage, convulsions, kidney failure, and even death (Sun et al., 2012; Wang et al., 2016). Besides, the discharging of 2,4-Dinitrophenol creates significant health risk such as hyperthermia, increased metabolism, skin allergy and cataracts, osteoporosis, cardiovascular disease and premature death (Shukla et al., 2009; Wang et al., 2000, 2009). The US Environmental Protection Agency listed Ph and DNP as priority pollutants and the recommended restriction on the concentrations in natural waters is lower than 10 ng L−1. Due to the high toxicity for environment and human, Ph and DNP should be completely removed from industrial effluents before discharge into water systems. Conventional treatments of Ph and DNP contaminated wastewater include advanced oxidation, biological, chemical oxidation
Corresponding author., Corresponding author. E-mail addresses: [email protected] (P.Q. Thang), [email protected] (K. Jitae), [email protected] (B.L. Giang), [email protected], [email protected] (P.T. Huong). ∗
∗∗
https://doi.org/10.1016/j.jenvman.2019.109556 Received 10 May 2019; Received in revised form 28 August 2019; Accepted 7 September 2019 Available online 18 September 2019 0301-4797/ © 2019 Elsevier Ltd. All rights reserved.
Journal of Environmental Management 251 (2019) 109556
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and adsorption (Nguyen et al., 2016; Pan et al., 2016; Das et al., 2018; Rene et al., 2018a, 2018b; Hao et al., 2018). The adsorption method is intensely used for removing organic and inorganic pollutants without the generation of hazardous by-products (Yakout, 2017; Mohammed et al., 2018; Sun et al., 2012) being inexpensive, while the equipment is simple, easy to operate and highly effective. Activated carbon is one of the most commonly used adsorbent in adsorption process due to its high surface area per unit mass. However, due to the high expense of activated carbon, many attempts have been made to develop low-cost adsorbents by using naturally present materials to remove toxic organic pollutants such as Ph and DNP. Recently, interest has grown in different aspects of the preparation of biochar to utilize their favorable properties for adsorption processes (Tran et al., 2015; Mohammed et al., 2018; Yakout, 2017; Mallek et al., 2018; Mishra et al., 2019; Sun et al., 2019). Production of biochar based on the pyrolysis of biological feedstock materials generally derived from bio-wastes such as forestry waste, poultry litter, activated sludge, algal biomass and crop residues (Hao et al., 2018; Oh and Seo, 2019; Zeng et al., 2019). Thermal pyrolysis can convert almost of biomass into biochar and the life cycle assessment of pyrolysis-biochar systems suggested that it is more environmentally as compared to the chemical treatment method. Biochar has been recognized as a good sorbent for different kinds of organic pollutants such as polycyclic aromatic hydrocarbons, polychlorinated biphenyls, volatile organic compounds and pesticide (Varjani et al., 2019; Oh and Seo, 2019; Kang et al., 2019). Also, biochar was applied for removal of various inorganic contaminants including heavy metals, nitrate and phosphate (Bardestani et al., 2019; Pham et al., 2016a, 2016b; Coleman et al., 2019). Viet Nam is an agricultural country in Southeast Asia, with a total agricultural land area of 26.28 million ha (79.4% of total land). Agriculture products are the most important economic sector in Vietnam and it produces large amounts of biomass resources such as rice husk, bagasse, coffee husk, wood chips and poultry litter. The national poultry population was 254.6 million, including 185.2 million chickens (72.8%) and 68.9 million water-birds (27.2%). The number of chickens is rising year by year leading to an increase in chicken manure biomass. Thereafter, farmers often use chicken manure for spread onto agricultural land as a means of disposal. However, composted chicken manure is a significant threat to water and air pollution due to the release of methane, ammonia or other organic compounds. Most previous studies have been done with using of chicken manure for biodiesel production (Jung et al., 2017, 2018) and energy recovery (Lee et al., 2017). There are few studies develop the potential of chicken manure as adsorbent for CO2 capture (Nguyen and Lee., 2016) and adsorption of heavy metal (Do and Lee, 2015). Due to the lack of experimental and theoretical study of converting chicken manure into biochar and apply as low-cost adsorbent for wastewater treatment. Therefore, it is challenging to develop an efficient adsorbent with low secondary pollution, non-released by-products, and especially environmental non-toxicity for the removal of organic pollutants such as Ph and DNP. However, to the best of our knowledge, no available study has examined the adsorption of Ph and DNP using CBC from wastewaters. The novelty of this work included a newly determined the application chicken manure biochar as of adsorbent for removal of toxic Ph and DNP from industrial wastewaters. This study also provided the presentation of detailed adsorbent preparation, adsorption kinetic, adsorption isotherms and recycling of material for further practical applications in large scale. The outcome of this study can bring a new idea for waste management in order to reduce environmental pollution in Vietnam.
Table 1 Properties of adsorbed. Adsorbed
Structure
Molecule weight (g mol−1)
pKa
Dipole moment
Log Kow
Ph
94.113
9.3
1.4D
1.67
DNP
184.11
4.1
5.7D
1.46
2. Materials and methods 2.1. Materials The chemicals used in this study including phenol (C6H5OH), 2,4dinitrophenol (C6H4N2O5), ethanol (C2H5OH), hydrochloric acid (HCl) and sodium hydroxide (NaOH) were purchased from Sigma-Aldrich Co., USA. The chemicals were of reagent grade and were used without further purification. All require solutions were prepared using deionized (DI) water. Phenol and 2,4-Dinitrophenol with basis physicalchemical properties are shown in Table 1. 2.2. Preparation of adsorbent The material in this study was prepared according to previously reported method (Lee et al., 2017). Chicken manure biomass was collected from a chicken farm in the city of Hanoi, Vietnam. It was dried in oven at 100 °C for 12 h and pulverized to a smaller size (less than 2 mm) using a commercial electric grinder. The chicken manure was pyrolyzed at temperature range from 200 to 600 °C for 2 h using a tube-type electrical furnace under N2 gas at 500 cc min−1. After cooling to the room temperature (22 ± 1 °C), the pyrolyzed chicken manure biochar was taken out and keep in an airtight plastic container for further experiments. 2.3. Characterization of adsorbent Scanning electron microscopy (SEM) system (Hitachi S4700, HighTechnologies Co., Japan) was used to observe the surface morphology of adsorbents. The surface functional groups present in the materials were identified by the Fourier transform infrared (FTIR) spectrometer (Thermo Nicolet Nexus, Model-S470, Thermo Fisher Scientific Inc., USA), in the range of 400–4000 cm−1. The samples were prepared by pressing a grounded mixture of 1% adsorbent with 99% dry KBr. The elemental analysis used to determine composition of carbon, hydrogen, oxygen and nitrogen by using an Elementar Analyzer (5E Series, Micromeritics Co., USA). The specific surface area and pore volume of adsorbents were measured using a five-point BET method under nitrogen atmosphere using a surface area and porosity analyzer (SA-9600 Series, Micromeritics Co., USA). 2.4. 4. Adsorption and desorption experiments Adsorption experiments were carried out by agitating 0.3 g of adsorbent in 50 mL of solution containing Ph or DNP at desired concentrations (10, 50,100, 150 and 200 mg L−1), solution pH = 7.0 and the contact time 0–180 min with a mechanical shaker rotating at 250 rpm. At each time, the sample was taken out and filtered by using a 0.45 μm membrane filter. The concentrations of Ph and DNP in the 2
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sampling solution were measured by monitoring the absorbance at 270 and 358 nm, respectively using a UV–Vis spectrophotometer (UV- 1900, Shinmadzu Co., Japan). The solution pH was adjusted to 7.0 by using 0.1 M HCl and 0.1 M NaOH solutions and measured by a pH meter (Orion Star A320, Thermo Fisher Scientific Inc., USA). The effect of the adsorbent dosage was investigated by applying different amounts of CBC at 0.1, 0.2, 0.3, 0.5, 1.0 and 2.0 g into 50 mL of Ph or DNP solution (50 mg L−1) for an equilibrium time of 180 min. The Langmuir and Freundlich isotherms were adopted for the adsorption of Ph and DNP (see in the supplementary information text S1). In addition, the adsorption kinetics of Ph and DNP onto CBC were determined using two common kinetic models, namely the pseudo-firstorder (FO) and pseudo-second-order (SO). The Kinetic models based on the FO and SO equations were used to interpret the adsorption data (refer to the supplementary information text S2). Each experiment was repeated at least three times and their mean values were obtained. The removal efficiency and adsorption capacity of adsorbed were calculated using equations (1) and (2), respectively.
Removal efficiency (%) =
qe =
(C0
(C0
Ce ) C0
× 100
3. Results and discussions 3.1. Characteristics of adsorbents The total surface areas and elementals composition of CBC at different temperature were analyzed and the results were listed in Table 3. It can be observed, the content of carbon increases from 38.9% at 200 °C to 54.3% at 500 °C, then slightly decreases to 46.4% at 600 °C. This is due to the detachment of functional groups, containing oxygen and hydrogen as previous reports (Oh and Seo, 2016; Bardestani et al., 2019; Oh and Seo, 2019). Therefore, the optimum reaction temperature for pyrolysis was selected at 500 °C, which can produced highest carbon-rich of CBC. Besides, the surface area of CBC increases rapidly to 168.8 m2 g−1 at 500 °C, which was much higher than that of raw material (21.3 m2 g−1). The result indicated that the pyrolysis process successfully developed the microporous structure, activated sites and the specific surface area of CBC (Bardestani et al., 2019; Coleman et al., 2019). In addition, the comparison of surface area from various types biomass was made (refer to Supplementary Information Table S1). The surface area of CBC was substantially higher than those reported of biochar produced from agricultural wastes such as cow manure (1.77 m2 g−1), chicken manure (6 m2 g−1), rice husk (24.6 m2 g −1), rice straw (10.7 m2 g−1), corn stalks (16.8 m2 g−1) oak tree (12.9 m2 g−1) and coffee grounds (18.7 m2 g−1). The previous studies by (Hao et al., 2018; Sun et al., 2019; Varjani et al., 2019; Zeng et al., 2019) have been reported the significant increase in surface area of adsorbent leading to enhance the adsorption performance of organic pollutants from water. Therefore, CBC would be good candidate as potential adsorbent for removal of organic pollutants. The results from BET and elemental analysis were consisted with the development of a microporous structure and surface functional groups of CBC characterization observed by SEM analysis (Fig. 1). The surface of chicken manure biomass was flat without porosity structure (Fig. 1(a) and (b)) while the CBC had irregular and porous surfaces (Fig. 1(c) and (d)). In addition, the CBC surface consisting large of pore and activate sites (Fig. 1 (d)); such morphology confers a relatively high surface area. This observation is supported by the surface areas (BET) analysis of the CBC above. It is known that the increase in the surface area and porosity leads to improve the adsorption performance of pollutants (Jin et al., 2018; Coleman et al., 2019; Bardestani et al., 2019). Finally, the development of surface functional groups and the surface charge of adsorbent were identified by FTIR and the point of zero charge (pHpzc), respectively. The details of analytical method and the results are shown in supplementary information (refer to text S3, S4 and Figs. S1 and S2).
(1)
Ce) × V m
(2) −1
where, C0 and Ce (mg L ) are the initial and equilibrium concentration, respectively. W (g) is the weight of the adsorbent and V (L) is the volume of the solution. qe (mg g−1) is adsorption capacity. 2.5. 5. Regeneration The regeneration process was carried on five cycles of adsorptiondesorption. After adsorption experiment, the Ph or DNP loaded onto CBC was taken out of solution, dried at 30 °C for 5 h and used for regeneration experiments. Then, the dried material above was added to the 100 mL of 30% C2H5OH solution for a contact time of 180 min at room temperature 22 ± 1 °C. After desorption, the adsorbent was separated from solution, washed with distilled water, dried and reused for another adsorption cycle. The desorption efficiency was calculated using Eq. (3):
Desoprion efficiency (%) =
(Cad
Cd ) Cad
× 100
(3)
where Cad (mg L−1) is concentration of adsorbed Ph or DNP, Cd (mg L−1) is concentration of desorbed Ph or DNP. 2.6. 6. Removal of Ph and DND from wastewaters Two different wastewater samples named WT1 and WT2 were obtained from wastewater treatment plant located in Dong Anh district, Hanoi, Vietnam. The basic properties of wastewaters were characterized after primary treatment processes including screening and grit removal (see in Table 2). The wastewaters contained a high concentration of Ph (87.2 mg L−1) and DNP (108.1 mg L−1), along with others inorganic pollutants. To assess the applicability of the CBC in industrial wastewater, the removal of Ph and DNP were subsequently conducted as descried in section 2.4 (under optimized conditions of pH 7.0, adsorbent dosage of 0.3 g and contact time of 90 min).
3.2. Removal of Ph and DNP experiments 3.2.1. Effect of adsorbent dose and reaction time on the removal of Ph and DNP Fig. 2(a) showed the removal efficiencies of Ph and DNP by CBC as function of adsorbent dose. The removal efficiencies of Ph and DNP per unit weight of adsorbent rapidly increased with increasing dose of CBC to a maximum of 89.6 and 97.3% at 0.3 g, after which there was no appreciable change in the removal efficiencies of Ph and DNP. The increase in the removal efficiency of pollutant due to the availability of
Table 2 Properties of wastewater samples. Samples
COD (mg L−1)
TOC (mg L−1)
BOD (mg L−1)
pH
Ph (mg L−1)
DNP (mg L−1)
Cl− (mg L−1)
NO3− (mg L−1)
WT1 WT2
125.4 151.3
241.3 298.6
92.7 113.6
9.98 5.37
87.2 –
– 108.1
423 328.5
189.7 162.7
3
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Table 3 Elemental and surface area analysis. Pyrolysis condition
100 °C 200 °C 300 °C 400 °C 500 °C 600 °C
(under (under (under (under (under (under
air – oven) N2 gas – furnace) N2 gas – furnace) N2 gas – furnace) N2 gas – furnace) N2 gas – furnace)
BET surface area (m2 g−1)
Elemental composition (% wt.) C
O
H
N
Others
21.3 35.1 41.5 66.7 68.8 54.2
34.4 38.9 43.3 51.8 54.3 46.4
21.6 20.8 19.7 16.3 18.8 19.7
13.3 12.7 11.5 8.8 10.5 10.6
5.7 5.2 4.9 5.7 4.5 4.3
25.3 22.3 20.6 18.4 11.9 11.8
more number of binding sites or activated site on the adsorbents surface (Pan et al., 2016; Sun et al., 2019; Bardestani et al., 2019). Any further increase in adsorbent dosage did not contribute to any increase in removal efficiency of Ph and DNP. Based on the result, the adsorbent dose of 0.3 g was chosen as optimum dosage for further experiments. The equilibrium time of adsorption is important parameter to develop method for wastewater treatment in pilot-scales. The adsorption behavior of Ph and DNP by CBC as function of reaction time are presented in Fig. 2(b). It can be seen that, the removal of phenolic compounds increased with increasing reaction time from 10 to 60 min, then plateaued after the reaction reached equilibrium (at 90 min). The adsorption equilibrium was obtained at a reaction time of 90 min for Ph and DNP with removal efficiencies of 83.5 and 98.6%, respectively. The adsorption of Ph and DNP by CBC were very quick in the first 90 min of the experiment, while no significant changes were observed after that, implying that the adsorption process had already reached the equilibrium state at 90 min. This result might be due to the availability of a huge number of vacant sites saturated with time. As a rule of thumb, by increasing contact time the availability of adsorbate molecules to unoccupied active sites on the adsorbent surface decreases, and as a result, these sites are ultimately saturated when the process reaches the equilibrium state (Coleman et al., 2019; Kang et al., 2019; Jang and Kan, 2019). Hence, the optimal reaction time for the adsorption of Ph
and DNP using CBC were maintained at 90 min. 3.2.2. Adsorption kinetics The results of adsorption kinetic-related values for Ph and DNP using CBC are presented in Table 4 and Fig. S3 (supplementary information). It demonstrated that the correlation coefficient from FO (R2 < 0.65) was lower than that of SO model (R2 > 0.95), confirming that the experimental data obey the SO kinetic model. However, the qe,cal value of the SO model for Ph and DNP were 28.7 and 26.5 mg g−1, respectively, which were more close to the qe,exp value (around 29.1 mg g−1), suggesting that the SO model fitted well to describe the adsorption behavior of Ph and DNP onto CBC. This revealed that chemisorption is the dominant mechanism in the adsorption process, which involves short-range interactions of π–π and hydrogen bonding between functional groups of adsorbent and adsorbed. The results from adsorption kinetics of this work are in-line with those of previous works using biochar for removal of organic pollutants (Varjani et al., 2019; Kang et al., 2019). 3.2.3. Effect of initial concentration The effect of initial concentration on the removal of Ph and DNP using CBC was investigated and the results are showed in Fig. 3. As the initial concentration increase from 10 to 200 mg L−1, the removal
Fig. 1. SEM analysis. (a) and (b): Surface morphology of chicken manure biomass. (c) and (d): Surface morphology of chicken manure biochar. 4
Journal of Environmental Management 251 (2019) 109556
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Fig. 2. (a). Effect of adsorbent dose on the removal of Ph and DNP. Fig. 2 (b). Effect of reaction time on the removal of Ph and DNP.
5
Journal of Environmental Management 251 (2019) 109556
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in the initial concentration of pollutants also reduced the adsorption capacity due to impossible of surface area and activated on the surface of adsorbent (Kang et al., 2019; Oh and Seo, 2019).
Table 4 Adsorption kinetics parameters. First-order kinetic model −1
Adsorbed
qexp (mg g−1)
k1 (min
Ph DNP
29.3 29.1
0.10 0.05
)
Second-order kinetic model 2
qe, cal (mg g−1)
R
k2 (g (mg min)−1)
qexp (mg g−1)
R2
18.6 14.9
0.31 0.60
0.05 0.02
28.7 26.5
0.99 0.96
3.2.4. Adsorption isotherm The adsorption parameters and their data fitting of two adsorption isotherm models are given in Table S2. The plot of Langmuir isotherm model Ce/qe against Ce and the slope and intercept plot of log qe against log Ce for the Freundlich model are shown in Fig.S4 (a) and S4 (b), respectively. The values of maximum adsorption capacity (qmax), and KL corresponding to the R2 which were calculated by the Langmuir plots. The correlation coefficient (R2) of Ph and DNP from the Langmuir isotherm model were significantly higher (R2 ≥ 0.98) than that of the Freundlich model (R2 ≤ 0.40). The higher relative correlation coefficient of the Langmuir isotherm model indicated that it better described the phenolic adsorption on CBC. The result also investigated that the adsorption of Ph and DNP onto CBC followed the unilayer adsorptive mechanism with a homogenous distribution of active sites. This means that a monolayer of adsorbate was formed on the surface of adsorbent and no further adsorption occurs after complete coverage of the active surface. This model also is valid for monolayer adsorption onto a surface exhibiting a finite number of identical sites (Pham et al., 2016a, 2016b; Bardestani et al., 2019; Coleman et al., 2019). Based on the Langmuir isotherm, the maximum adsorption capacity of Ph and DNP were found to be 106.2 and 148.1 mg g−1, respectively. Recently, various alternative adsorbents produced from forest, agricultural byproducts have been used for adsorption of Ph and DNP from aqueous solution (see in Table 5). The biochar from bamboo biomass showed highest value of qmax for Ph (166.7 mg g−1), which was slightly higher than this study (106.2 mg g−1). The maximum adsorption capacity of Ph provided by other biochar such as pine fruit shell (26.7 mg g−1), rice straw (80.5 mg g−1), granulated cork (0.9 mg g−1), rice husk (14.4 mg g−1), coconut shell biochar (19.9 mg g−1) or even commercial activated carbon (69.9 mg g−1) were much lower than in this study. In addition, the removal of DNP using biochar as adsorbent was done by showed very low adsorption capacity of DNP (32.26 mg g−1) as compared to CBC (148.1 mg g−1). These results demonstrate the potential of the CBC as an alternative adsorbent for removal of Ph and DNP from water. Nevertheless, the other advantages include a simple production process,
Fig. 3. Effect of initial concentration on the removal of Ph and DNP.
efficiencies of Ph and DNP decreased from 98.8 to 80.5% and 98.2 to 81.7%, respectively. At low initial concentration, the surface area and activate site of CBC are available for the contribution as well as the improvement in the adsorption capacity of phenolic compounds (Varjani et al., 2019; Oh and Seo, 2016). The removal efficiency of Ph and DNP were declined at high initial concentration due to the competition of phenolic compounds molecules onto the limited surface or activated site of CBC. As previous reported by other studies, an increase
Table 5 Comparisons of maximum adsorption capacity for Ph and DNP by different biochar adsorbents. Adsorbents
Adsorbates
Conditions
qmax (mg g−1)
Mechanism
References
Mohammed et al. (2018) Yakout (2017) Mallek et al. (2018)
o
pH
Temp ( C)
Pine fruit shell (heat treatment 550 °C)
Ph
6.5
25
26.73
Rice straw (heat treatment 550 °C) Granulated cork (Without heat treatment) Rice husk (heat treatment 550 °C) Corn husk 500 °C Commercial activated carbon Coconut shell biochar 500 °C Bamboo biochar 550 °C Chemical modification of Kola nut CBC
Ph Ph
7.0 6.0
25 20
80.5 0.92
Dispersive interaction, electrostatic interaction and π-π interaction NA π-π interaction
Ph Ph
6.0 7.0
22 25
14.4 8.44
NA Electro-donor, π-π interaction
Tran et al. (2015) Mishra et al. (2019)
Ph Ph
5.0 7.0
20 25
69.95 19.94
Hydrophilicity interaction Van der Waals' force, π-π interaction
Sun et al. (2019) Hao et al. (2018)
Ph
6.0
20
166.72
NA
Jin et al., 2018
DNP Ph
7.0 7.0
25 22
32.26 106.2
CBC
DNP
7.0
22
148.1
Surface diffusion, pore diffusion and interior sites electrostatic interaction, hydrogen bonding and π-π interaction electrostatic interaction, hydrogen bonding and π-π interaction
6
This study This study
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deprotonated form (DNP−) when the pH = 7.0. The adsorbent surface charge and the deprotonated form of DNP adsorbate both suggest that stronger electrostatic interaction occurred between CBC and DNP as compared to Ph.
low-cost as compared to commercial activated carbon, the widespread availability of waste feedstock and concurrent waste management. This suggests that CBC can be a promising adsorbent for treatment of Ph and DNP in wastewater. The Freundlich isotherm is derived by assuming a heterogeneous surface with a non unifrom distribution of adsorption heat over the surface through a multilayer adsorption process. The constant KF is an approximate indicator of the adsorption capacity of Ph and DNP onto CBC. From Table S2, it can be seen that the KF values of Ph and DNP were 85.3 and 97.6 mg g-1, respectively. In spite of the lower correlation coefficients of the experimental data with Freundlich model by comparing to the Langmuir model, the same hierarchy of adsorption capacity was obtained: Ph < DNP. Moreover, the value of 1/n could be considered both a function of the strength of adsorption and heterogeneity parameter (if 1/n = 1, adsorption is linear; 1/n > 1, it is chemical and 1/n < 1, adsorption is physical favorable process). The heterogeneity factor (1/n) were 0.32 and 0.47 for Ph and DNP, respectively. The results suggested that adsorption of Ph and DNP onto CBC in favorable physics sorption and the Freundlich isotherm is a less appropriate isotherm than the Langmuir (Pham et al., 2016a, 2016b; Pan et al., 2019; Zeng et al., 2019).
3.2.7.2. The π-π interaction. Considering the π-bond interaction between the benzene ring of phenolic pollutants and the π electron distribution bonded to the CBC edges, the increase in the dispersive adsorption potential of the adsorbent surface increases the adsorption capacity on the CBC surface (Xing et al., 1994; Mishra et al., 2019; Zeng et al., 2019). In the π-π interaction, the oxygen-containing functional groups of CBC surface act as electron donors and the aromatic rings of phenolic pollutants act as electron acceptors (Yang and Xing, 2010). The surface functional groups of CBC such as –COOH and –OH play a certain role in the adsorbing phenolic pollutants (Heibati et al., 2014). The concept of the π-π interaction mechanism assumes charge transfer between the π electrons of the benzene ring and the π electron distribution bonded to the CBC surface, leading to the increase in the uptake capacity of Ph and DNP onto the adsorbent (Oh and Seo, 2016; Kang et al., 2019). Moreover, Coughlin and Ezra (1968) confirmed the π-π interaction between the π-electrons of the aromatic rings of an adsorbate and the π-electrons of a carbonaceous adsorbent. From Table 1, it can be seen that, the DNP molecule presented two polar nitro-functional group (as strong electron acceptors) on the benzene ring, leading to strong π-π interaction between CBC and DNP. Therefore, more adsorption capacity of DNP onto CBC is expected compared to that of Ph.
3.2.5. Regeneration Recovery of adsorbent is important process in order to evaluate the economical of adsorption process. The CBC showed high adsorption capacity and desorption efficiency for both of Ph and DNP (see in Fig. 4(a) and b). The desorption efficiencies of Ph and DNP were close to 100% for the first and the second cycles, then decreased by 31.3 and 23.6% at the fifth cycles, respectively. Besides, the CBC showed high adsorption capacities of Ph and DNP for the first three cycles and slightly decreased (less than 20%) after five repeated cycles. This high reusability, combined with facile regeneration characteristics and high adsorption capacity, demonstrated the potential use of the CBC as promising adsorbent for treatment of wastewater containing phenolic compounds (Oh and Seo, 2019; Varjani et al., 2019).
3.2.7.3. Hydrogen bond. Finally, the hydrogen bonding contributed as one of the strongest interaction mechanisms between CBC and phenolic compounds. The hydrogen bonding takes place by the sharing of electrons between CBC and adsorbate (Ph and DNP). Hydrogen bonding interactions can occur as follows: (a) between surface hydrogens of the hydroxyl groups (H-donor) on the CBC′ surface and the appropriate atoms (nitrogen and oxygen; H-acceptor) of phenolic, and (b) between the hydroxyl groups on the CBC′ surface and the aromatic rings in Ph and DNP molecules (Coughlin and Ezra, 1968; Heibati et al., 2014; Tran et al., 2017; Kang et al., 2019). Therefore, the surface hydroxyl groups such as –OH and –COOH of adsorbent interact with –OH and –NO2 groups of adsorbate to form hydrogen bonds at various positions, which enhances the adsorption capacity (Mishra et al., 2019; Zeng et al., 2019). In addition, the surface of the CBC has the point of zero charge (pHpzc) at around pH 7.11 ± 0.1 (Fig. S2). The point of zero charge can be defined as the suspension pH at which a surface has a net charge of zero. When the pH is lower than pHpzc, the surface of adsorbent has net positive charge and if the pH > pHpzc, the surface of adsorbent has net negative charge. On the other hand, the pKa values of Ph and DNP were 9.3 and 4.1, respectively. Under the neutral solution (pH = 7.0), the adsorption of DNP could be increased more than that for Ph due to its relatively greater negative charge. Moreover, the dipole moment of Ph (1.4D) is smaller than that of DNP (5.7D), leading that DNP can easily interact with the surface of CBC. In general, the dipole-dipole force interaction is considered as a rational adsorption mechanism (Xing et al., 1994; Oh and Seo, 2019). The larger dipole moment of DNP can increase the bonding with CBC, which then promotes a certain synergistic DNP adsorption capacity. This phenomenal was confirmed by the identified maximum adsorption capacity of DNP (148 0.1 mg g−1), which was much higher than that of Ph (106.g mg g−1).
3.2.6. Filed application in wastewaters Fig. 5 displayed the removal efficiency of Ph and DNP from wastewaters using CBC. The wastewater samples contain relatively high concentration of phenolic compounds and others different contaminants (Table 2). CBC showed excellent removal efficiencies for Ph and DNP at around 78.5 and 83.4%, respectively. Therefore, biochar derived from chicken manure can be successfully applied as low-cost adsorbent for removal of Ph and DNP in wastewater. 3.2.7. Adsorption mechanism Due to the lack of experimental and theoretical research and unavailable data on the Ph and DNP adsorption characteristics from solution using CBC, the development of a plausible description for the Ph and DNP adsorption mechanism will expand our understanding of the adsorbent-adsorbate interaction mechanisms. The Ph and DNP can be adsorbed easily onto the surface of CBC due to its high surface area, high porous structure and containing large oxygen surface functional groups (confirmed by SEM, BET and FTIR analysis). Fig. S5 shows the possible adsorption mechanisms of Ph and DNP onto CBC, which can be considered as the result of major mechanisms listed below: 3.2.7.1. Electrostatic interaction. Under the neutral solution (pH = 7.0) the surface of CBC is positively charged while the DNP and Ph are negatively charged because of the electron-rich benzene ring. Therefore, Ph and DNP will be attracted towards the positively charged CBC surface, resulting in the removal of Ph and DNP from the solution. Besides, the pKa values of Ph and DNP were 9.3 and 4.1, respectively, thus the Ph existed in neutral form and the DNP existed in
3.2.8. Practical applications and future research Water quality is a serious environmental problem presently faced by many countries or communities (Nguyen et al., 2016; Rene et al., 2018a, 2018b; Varjani et al., 2019). It is becoming a global challenge to 7
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Fig. 4. (a). Desorption efficiency of Ph and DNP. Fig. 4 (b). Desorption capacity of Ph and DNP.
ensure clean drinking water and clean up wastewater bodies contaminated by the causes of population growth, increased industrial activities, and frequent natural disasters (Ahmed et al., 2016; Antunes et al., 2017). A particularly important global issue is to develop more
efficient and cost-effective water treatment processes of organic pollutants in water. Phenol and 2,4-dinitrophenol are listed as priority pollutants due to their high toxicity and carcinogenicity properties. Therefore, the development technology which can completely remove 8
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Acknowledgements This work was supported by Duy Tan University. Appendix A. Supplementary data Supplementary data to this article can be found online at https:// doi.org/10.1016/j.jenvman.2019.109556. References Ahmed, M.B., Zhou, J.L., Ngo, H.H., Guo, W., Chen, M., 2016. Progress in the preparation and application of modified biochar for improved contaminant removal from water and wastewater. Bioresour. Technol. 214, 836–851. Antunes, E., Jacob, M.V., Brodie, G., Schneider, P.A., 2017. Silver removal from aqueous solution by biochar produced from biosolids via microwave pyrolysis. J. Environ. Manag. 203, 264–272. Bardestani, R., Roy, Ch, Kaliaguine, S., 2019. The effect of biochar mild air oxidation on the optimization of lead (II) adsorption. J. Environ. Manag. 240, 404–420. Coleman, B.S.L., Easton, Z.M., Bock, E.M., 2019. Biochar fails to enhance nutrient removal in woodchip bioreactor columns following saturation. J. Environ. Manag. 232, 490–498. Coughlin, R.W., Ezra, F.S., 1968. 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Phenol adsorption on biochar prepared from the pine fruit shells: equilibrium, kinetic and thermodynamics studies. J. Environ. Manag. 226, 377–385. Nguyen, M.V., Lee, B.K., 2016. A novel removal of CO2 using nitrogen doped biochar beads as a green adsorbent. Process Saf. Environ. Prot. 104, 490–498. Nguyen, T.T., Thanh, B.X., Nguyen, D.D., Dan, N.P., Ngo, H.H., Guo, W., 2016. Performance and membrane fouling of two types of laboratory-scale submerged membrane bioreactors for hospital wastewater treatment at low flux condition. Separ. Purif. Technol. 165, 123–129. Oh, S.Y., Seo, Y.D., 2016. Sorption of halogenated phenols and pharmaceuticals to biochar: affecting factors a mechanism. Environ. Sci. Pollut. Res. 23, 951–961. Oh, S.K., Seo, Y.D., 2019. Factors affecting the sorption of halogenated phenols onto polymer biomass-derived biochar: effects of pH, hydrophobicity, and deprotonation. J. Environ. Manag. 232, 145–152. Pan, Y., Li, Z., Zhang, Z., Tong, X.S., Li, H., Jia, C.Z., Liu, B., Sun, C.Y., Yang, L.Y., Chen, G.J., 2016. Adsorptive removal of phenol from aqueous solution with zeolitic imidazolate framework-67. J. Environ. Manag. 169, 167–173. Pan, J., Ma, J., Liu, X.X., Zhai, L., Quyang, X.H., Liu, H.B., 2019. Effects of different types of biochar on the anaerobic digestion of chicken manure. Bioresour. Technol. 275, 258–265. Pham, T.H., Lee, B.K., Kim, J.T., Lee, C.H., 2016a. Nitrophenols removal from aqueous medium using Fe-nano mesoporous zeolite. Mater. Des. 101, 210–217. Pham, T.H., Lee, B.K., Kim, J.T., Lee, C.H., Chong, M.N., 2016b. Acid activation pine cone
Fig. 5. Removal of Ph and DNP from wastewaters.
Ph and DNP is needed. The production of biochar from agricultural wastes (chicken manure) in Vietnam showed high removal efficiency of Ph and DNP from industrial wastewaters. The low-cost of adsorbent, simple operation process for wastewater treatment along with no generation of by-products which can support CBC as a promising adsorbent for treatment of organic pollutants in wastewater. The results from this study could guide future research on development of biochar from agricultural wastes in Vietnam. A huge amount of agricultural wastes is directly effect to the environmental sustainability, thus converting wastes into add-value material like biochar could be an option for solid waste management as well as economic potential. The prices of biochar can be significantly lower than the prices of commercial activated carbon, leading to reduce operation cost for the wastewater treatment. However, it needs improve the research to some extent in the view which are listed below: 1. To develop the method for productions of biochar from other wastes in Vietnam such as coffee husk, rice husk, coconut shell and poultry litters. 2. To develop the modification method of biochar to improve the removal efficiency of organic pollutants. 3. To investigate the potential application of CB for removal of inorganic pollutants and nutrient form wastewaters. 4. To develop the pilot –scale for treatment of organic pollutants and so far can improve the quality of biochar in order to replace of expensive commercial activated carbon. 5. To extend the application of biochar for improving the soil quality. 4. Conclusions This study investigated the potential of biochar derived from chicken manure towards toxic phenol and 2,4-dinitrophenol in wastewaters. The CBC exhibited higher adsorption capacities for Ph and DNP than other previously reported materials. CBC also showed an excellent removal efficiency of Ph and DNP from real wastewaters along with high stability up to five cycles. The results collectively indicate that CBC could be used as a promising low-cost, recyclable adsorbent for treatment of organic pollutants in wastewaters. Conflict of interests The authors do not have any conflict of interests to declare. 9
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P.Q. Thang, et al. waste at different temperature and selective removal of Pb2+ ions in water. Process Saf. Environ. Prot. 100, 80–90. Rene, E.R., Shu, L., Jegatheesan, V., 2018a. Environmentally friendly (bio) technologies for the removal of emerging organic and inorganic pollutants from water. J. Water Supply Res. Technol. - Aqua 67, 697–702. Rene, E.R., Shu, L., Lens, P.N.L., Jegatheesan, J.V., 2018b. Tools, techniques, and technologies for pollution prevention, control, and resource recovery. Environ. Sci. pollut. R . 25, 5047–5050. She, Z.L., Gao, M.C., Jin, C.J., Chen, Y.Y., Yu, J.W., 2005. Toxicity and biodegradation of 2,4-dinitrophenol and 3-nitrophenol in anaerobic systems. Process Biochem. 40, 3017–3024. Shukla, S., Dorris, K., Chikkaveeraiah, B., 2009. Photocatalytic degradation of 2,4-dinitrophenol. J. Hazard Mater. 164, 310–314. Sun, J.Q., Xu, L., Tang, Y.Q., Chen, F.M., Wu, X.L., 2012. Simultaneous degradation of phenol and n-hexadecane by Acinetobacter strains. Bioresour. Technol. 123, 664–668. Sun, J., Liu, X., Zhang, F., Zho, J., Wu, J., Alsaedi, A., Hayat, T., Li, J., 2019. Insight into the mechanism of adsorption of phenol and resorcinol on activated carbons with different oxidation degrees. Colloid.Surf.A. 563, 22–30. Tang, T., Yue, Zh, Wang, J., Chen, T., Qing, Ch, 2018. Goethite promoted biodegradation of 2,4-dinitrophenol under nitrate reduction condition. J. Hazard Mater. 343, 176–180. Tran, V.S., Ngo, H.H., Guo, W., Zhang, J., Liang, S., Ton-That, C., Zhang, X., 2015. Typical low cost biosorbents for adsorptive removal of specific organic pollutants from water. Bioresour. Technol. 182, 353–363. Tran, H.N., You, S.J., Chao, H.P., 2017. Fast and efficient adsorption of methylene green 5 on activated carbon prepared from new chemical activation method. J. Environ. Manag. 188, 322–336. Uddandarao, P., Hingnekar, T.A., Balakrishnan, R.M., Rene, E.R., 2019. Solar assisted
photocatalytic degradation of organic pollutants in the presence of biogenic fluorescent ZnS nanocolloids. Chemosphere 234, 287–296. Varjani, S., Kumar, G., Rene, E.R., 2019. Developments in biochar application for pesticide remediation: current knowledge and future research directions. J. Environ. Manag. 232, 505–513. Vinati, A., Rene, E.R., Pakshirajan, K., Behera, S.K., 2019. Activated red mud as a permeable reactive barrier material for fluoride removal from ground water: parameter optimization and physico-chemical characterization. Environ. Technol. 19, 1–12. Wang, C.C., Lee, C.M., Kuan, C.H., 2000. Removal of 2,4-dichlorophenol by suspended and immobilized Bacillus insolitus. Chemosphere 41, 447–452. Wang, H., Wang, H., Jiang, W., Li, Z., 2009. Photocatalytic degradation of 2,4-dinitrophenol (DNP) by multi-walled carbon nanotubes (MWCNTs)/TiO2 composite in aqueous solution under solar irradiation. Water Res. 43, 204–210. Wang, Y., Chen, H., Liu, Y.X., Ren, R.P., Lv, Y.K., 2016. An adsorption-release-biodegradation system for simultaneous biodegradation of phenol and ammonium in phenol-rich wastewater. Bioresour. Technol. 211, 711–719. Xing, B., McGill, W.B., Dudas, M.J., Maham, Y., Hepler, L., 1994. Sorption of phenol by selected biopolymers: isotherms, energetics, and polarity. Environ. Sci. Technol. 28, 466–473. Yakout, S.M., 2017. Physicochemical characteristics of biochar produced from rice straw at different pyrolysis temperature for soil amendment and removal of organics. Proc. Natl. Acad. Sci., India, Sect. A Phys. Sci. 87, 207–214. Yang, K., Xing, B., 2010. Adsorption of organic compounds by carbon nanomaterials in aqueous phase: polanyi theory and its application. Chem. Rev. 110, 5989–6008. Zeng, T., Rene, E.R., Zhang, S., Lens, P.N.L., 2019. Removal of selenate and cadmium by anaerobic granular sludge: EPS characterization and microbial community analysis. Process Saf. Environ. Prot. 126, 150–159.
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Research article
Potential application of chicken manure biochar towards toxic phenol and 2, 4-dinitrophenol in wastewaters
T
Phan Quang Thanga,b, Kim Jitaec,∗∗, Bach Long Giangd,e, N.M. Vietc, Pham Thi Huongc,∗ a
Division of Computational Mathematics and Engineering, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam Faculty of Environment & Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Vietnam c Center for Advanced Chemistry, Institute of Research and Development, Duy Tan University, Da Nang, Vietnam d NTT Hi-Tech Institute, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh Street, Dist. 4, Ho Chi Minh City, Vietnam e Center of Excellence for Green Energy and Environmental Nanomaterials, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam b
ARTICLE INFO
ABSTRACT
Keywords: Adsorption Biochar Chicken manure Phenol 2,4-Dinitrophenol Mechanism
In this study, chicken manure biochar (CBC) was prepared and applied as adsorbent for the removal of phenolic pollutants including phenol (Ph) and 2,4-Dinitrophenol (DNP) from wastewaters. The feasibility analysis was focused on the adsorption effects of various factors, such as initial concentration, adsorbent dosage and reaction time. The results showed that BC could efficiently remove the Ph and DNP within 90 min of reaction time. Increasing of CBC dosage up to 0.3 g results in the maximum removal efficiency of Ph and DNP and lowers initial concentration which is beneficial for the adsorption of phenolic compounds. The second-order kinetic model and the Langmuir isotherm provided the best correlation with the adsorption data. Based on the Langmuir isotherm, maximum adsorption capacities (qmax) of Ph and DNP were found at 106.2 and 148.1 mg g−1, respectively. The obtained qmax values for CB were higher than those reported in literature on the adsorption of Ph and DNP using different biochar. Analyzing the regeneration characteristics, BC displayed high reusability with less than 20% loss in adsorption capacities of Ph and DNP, even after five repeated cycles. Investigation of the adsorption equilibrium under various conditions suggested several possible interaction mechanisms, including hydrogen bonding, electrostatic interaction and π- π bonding, which were attributed to the binding affinity of the adsorbent-adsorbate interaction. In the field application, the CBC showed an excellent removal efficiencies of Ph and DNP from industrial wastewaters (around 80% phenolic pollutants were removed). These findings support the potential use of CBC as effective adsorbent for treatment of wastewater containing Ph and DNP.
1. Introduction Environmental pollution is becoming a global issue with the rapid development of industrialization (Rene et al., 2018a, 2018b; Uddandarao et al., 2019; Vinati et al., 2019). Phenolic compounds such as phenol and 2,4-Dinitrophenol are common constituent of industrial wastewater produced from petroleum refineries, coal gasification plants, phenolic resin industries, pesticides, dyes, plastics manufacture and pharmaceutical industries. Phenol and 2,4-Dinitrophenol are recognized as emerging contaminants because of their high toxicity, high resistance to biodegradation and carcinogenicity properties even at low concentrations (She et al., 2005; Das et al., 2015; Pan et al., 2016; Pham et al., 2016a, 2016b; Tang et al., 2018). Exposure to phenol may result
in systemic poisoning, weakness, sweating, headache, shock, excitement, kidney damage, convulsions, kidney failure, and even death (Sun et al., 2012; Wang et al., 2016). Besides, the discharging of 2,4-Dinitrophenol creates significant health risk such as hyperthermia, increased metabolism, skin allergy and cataracts, osteoporosis, cardiovascular disease and premature death (Shukla et al., 2009; Wang et al., 2000, 2009). The US Environmental Protection Agency listed Ph and DNP as priority pollutants and the recommended restriction on the concentrations in natural waters is lower than 10 ng L−1. Due to the high toxicity for environment and human, Ph and DNP should be completely removed from industrial effluents before discharge into water systems. Conventional treatments of Ph and DNP contaminated wastewater include advanced oxidation, biological, chemical oxidation
Corresponding author., Corresponding author. E-mail addresses: [email protected] (P.Q. Thang), [email protected] (K. Jitae), [email protected] (B.L. Giang), [email protected], [email protected] (P.T. Huong). ∗
∗∗
https://doi.org/10.1016/j.jenvman.2019.109556 Received 10 May 2019; Received in revised form 28 August 2019; Accepted 7 September 2019 Available online 18 September 2019 0301-4797/ © 2019 Elsevier Ltd. All rights reserved.
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and adsorption (Nguyen et al., 2016; Pan et al., 2016; Das et al., 2018; Rene et al., 2018a, 2018b; Hao et al., 2018). The adsorption method is intensely used for removing organic and inorganic pollutants without the generation of hazardous by-products (Yakout, 2017; Mohammed et al., 2018; Sun et al., 2012) being inexpensive, while the equipment is simple, easy to operate and highly effective. Activated carbon is one of the most commonly used adsorbent in adsorption process due to its high surface area per unit mass. However, due to the high expense of activated carbon, many attempts have been made to develop low-cost adsorbents by using naturally present materials to remove toxic organic pollutants such as Ph and DNP. Recently, interest has grown in different aspects of the preparation of biochar to utilize their favorable properties for adsorption processes (Tran et al., 2015; Mohammed et al., 2018; Yakout, 2017; Mallek et al., 2018; Mishra et al., 2019; Sun et al., 2019). Production of biochar based on the pyrolysis of biological feedstock materials generally derived from bio-wastes such as forestry waste, poultry litter, activated sludge, algal biomass and crop residues (Hao et al., 2018; Oh and Seo, 2019; Zeng et al., 2019). Thermal pyrolysis can convert almost of biomass into biochar and the life cycle assessment of pyrolysis-biochar systems suggested that it is more environmentally as compared to the chemical treatment method. Biochar has been recognized as a good sorbent for different kinds of organic pollutants such as polycyclic aromatic hydrocarbons, polychlorinated biphenyls, volatile organic compounds and pesticide (Varjani et al., 2019; Oh and Seo, 2019; Kang et al., 2019). Also, biochar was applied for removal of various inorganic contaminants including heavy metals, nitrate and phosphate (Bardestani et al., 2019; Pham et al., 2016a, 2016b; Coleman et al., 2019). Viet Nam is an agricultural country in Southeast Asia, with a total agricultural land area of 26.28 million ha (79.4% of total land). Agriculture products are the most important economic sector in Vietnam and it produces large amounts of biomass resources such as rice husk, bagasse, coffee husk, wood chips and poultry litter. The national poultry population was 254.6 million, including 185.2 million chickens (72.8%) and 68.9 million water-birds (27.2%). The number of chickens is rising year by year leading to an increase in chicken manure biomass. Thereafter, farmers often use chicken manure for spread onto agricultural land as a means of disposal. However, composted chicken manure is a significant threat to water and air pollution due to the release of methane, ammonia or other organic compounds. Most previous studies have been done with using of chicken manure for biodiesel production (Jung et al., 2017, 2018) and energy recovery (Lee et al., 2017). There are few studies develop the potential of chicken manure as adsorbent for CO2 capture (Nguyen and Lee., 2016) and adsorption of heavy metal (Do and Lee, 2015). Due to the lack of experimental and theoretical study of converting chicken manure into biochar and apply as low-cost adsorbent for wastewater treatment. Therefore, it is challenging to develop an efficient adsorbent with low secondary pollution, non-released by-products, and especially environmental non-toxicity for the removal of organic pollutants such as Ph and DNP. However, to the best of our knowledge, no available study has examined the adsorption of Ph and DNP using CBC from wastewaters. The novelty of this work included a newly determined the application chicken manure biochar as of adsorbent for removal of toxic Ph and DNP from industrial wastewaters. This study also provided the presentation of detailed adsorbent preparation, adsorption kinetic, adsorption isotherms and recycling of material for further practical applications in large scale. The outcome of this study can bring a new idea for waste management in order to reduce environmental pollution in Vietnam.
Table 1 Properties of adsorbed. Adsorbed
Structure
Molecule weight (g mol−1)
pKa
Dipole moment
Log Kow
Ph
94.113
9.3
1.4D
1.67
DNP
184.11
4.1
5.7D
1.46
2. Materials and methods 2.1. Materials The chemicals used in this study including phenol (C6H5OH), 2,4dinitrophenol (C6H4N2O5), ethanol (C2H5OH), hydrochloric acid (HCl) and sodium hydroxide (NaOH) were purchased from Sigma-Aldrich Co., USA. The chemicals were of reagent grade and were used without further purification. All require solutions were prepared using deionized (DI) water. Phenol and 2,4-Dinitrophenol with basis physicalchemical properties are shown in Table 1. 2.2. Preparation of adsorbent The material in this study was prepared according to previously reported method (Lee et al., 2017). Chicken manure biomass was collected from a chicken farm in the city of Hanoi, Vietnam. It was dried in oven at 100 °C for 12 h and pulverized to a smaller size (less than 2 mm) using a commercial electric grinder. The chicken manure was pyrolyzed at temperature range from 200 to 600 °C for 2 h using a tube-type electrical furnace under N2 gas at 500 cc min−1. After cooling to the room temperature (22 ± 1 °C), the pyrolyzed chicken manure biochar was taken out and keep in an airtight plastic container for further experiments. 2.3. Characterization of adsorbent Scanning electron microscopy (SEM) system (Hitachi S4700, HighTechnologies Co., Japan) was used to observe the surface morphology of adsorbents. The surface functional groups present in the materials were identified by the Fourier transform infrared (FTIR) spectrometer (Thermo Nicolet Nexus, Model-S470, Thermo Fisher Scientific Inc., USA), in the range of 400–4000 cm−1. The samples were prepared by pressing a grounded mixture of 1% adsorbent with 99% dry KBr. The elemental analysis used to determine composition of carbon, hydrogen, oxygen and nitrogen by using an Elementar Analyzer (5E Series, Micromeritics Co., USA). The specific surface area and pore volume of adsorbents were measured using a five-point BET method under nitrogen atmosphere using a surface area and porosity analyzer (SA-9600 Series, Micromeritics Co., USA). 2.4. 4. Adsorption and desorption experiments Adsorption experiments were carried out by agitating 0.3 g of adsorbent in 50 mL of solution containing Ph or DNP at desired concentrations (10, 50,100, 150 and 200 mg L−1), solution pH = 7.0 and the contact time 0–180 min with a mechanical shaker rotating at 250 rpm. At each time, the sample was taken out and filtered by using a 0.45 μm membrane filter. The concentrations of Ph and DNP in the 2
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sampling solution were measured by monitoring the absorbance at 270 and 358 nm, respectively using a UV–Vis spectrophotometer (UV- 1900, Shinmadzu Co., Japan). The solution pH was adjusted to 7.0 by using 0.1 M HCl and 0.1 M NaOH solutions and measured by a pH meter (Orion Star A320, Thermo Fisher Scientific Inc., USA). The effect of the adsorbent dosage was investigated by applying different amounts of CBC at 0.1, 0.2, 0.3, 0.5, 1.0 and 2.0 g into 50 mL of Ph or DNP solution (50 mg L−1) for an equilibrium time of 180 min. The Langmuir and Freundlich isotherms were adopted for the adsorption of Ph and DNP (see in the supplementary information text S1). In addition, the adsorption kinetics of Ph and DNP onto CBC were determined using two common kinetic models, namely the pseudo-firstorder (FO) and pseudo-second-order (SO). The Kinetic models based on the FO and SO equations were used to interpret the adsorption data (refer to the supplementary information text S2). Each experiment was repeated at least three times and their mean values were obtained. The removal efficiency and adsorption capacity of adsorbed were calculated using equations (1) and (2), respectively.
Removal efficiency (%) =
qe =
(C0
(C0
Ce ) C0
× 100
3. Results and discussions 3.1. Characteristics of adsorbents The total surface areas and elementals composition of CBC at different temperature were analyzed and the results were listed in Table 3. It can be observed, the content of carbon increases from 38.9% at 200 °C to 54.3% at 500 °C, then slightly decreases to 46.4% at 600 °C. This is due to the detachment of functional groups, containing oxygen and hydrogen as previous reports (Oh and Seo, 2016; Bardestani et al., 2019; Oh and Seo, 2019). Therefore, the optimum reaction temperature for pyrolysis was selected at 500 °C, which can produced highest carbon-rich of CBC. Besides, the surface area of CBC increases rapidly to 168.8 m2 g−1 at 500 °C, which was much higher than that of raw material (21.3 m2 g−1). The result indicated that the pyrolysis process successfully developed the microporous structure, activated sites and the specific surface area of CBC (Bardestani et al., 2019; Coleman et al., 2019). In addition, the comparison of surface area from various types biomass was made (refer to Supplementary Information Table S1). The surface area of CBC was substantially higher than those reported of biochar produced from agricultural wastes such as cow manure (1.77 m2 g−1), chicken manure (6 m2 g−1), rice husk (24.6 m2 g −1), rice straw (10.7 m2 g−1), corn stalks (16.8 m2 g−1) oak tree (12.9 m2 g−1) and coffee grounds (18.7 m2 g−1). The previous studies by (Hao et al., 2018; Sun et al., 2019; Varjani et al., 2019; Zeng et al., 2019) have been reported the significant increase in surface area of adsorbent leading to enhance the adsorption performance of organic pollutants from water. Therefore, CBC would be good candidate as potential adsorbent for removal of organic pollutants. The results from BET and elemental analysis were consisted with the development of a microporous structure and surface functional groups of CBC characterization observed by SEM analysis (Fig. 1). The surface of chicken manure biomass was flat without porosity structure (Fig. 1(a) and (b)) while the CBC had irregular and porous surfaces (Fig. 1(c) and (d)). In addition, the CBC surface consisting large of pore and activate sites (Fig. 1 (d)); such morphology confers a relatively high surface area. This observation is supported by the surface areas (BET) analysis of the CBC above. It is known that the increase in the surface area and porosity leads to improve the adsorption performance of pollutants (Jin et al., 2018; Coleman et al., 2019; Bardestani et al., 2019). Finally, the development of surface functional groups and the surface charge of adsorbent were identified by FTIR and the point of zero charge (pHpzc), respectively. The details of analytical method and the results are shown in supplementary information (refer to text S3, S4 and Figs. S1 and S2).
(1)
Ce) × V m
(2) −1
where, C0 and Ce (mg L ) are the initial and equilibrium concentration, respectively. W (g) is the weight of the adsorbent and V (L) is the volume of the solution. qe (mg g−1) is adsorption capacity. 2.5. 5. Regeneration The regeneration process was carried on five cycles of adsorptiondesorption. After adsorption experiment, the Ph or DNP loaded onto CBC was taken out of solution, dried at 30 °C for 5 h and used for regeneration experiments. Then, the dried material above was added to the 100 mL of 30% C2H5OH solution for a contact time of 180 min at room temperature 22 ± 1 °C. After desorption, the adsorbent was separated from solution, washed with distilled water, dried and reused for another adsorption cycle. The desorption efficiency was calculated using Eq. (3):
Desoprion efficiency (%) =
(Cad
Cd ) Cad
× 100
(3)
where Cad (mg L−1) is concentration of adsorbed Ph or DNP, Cd (mg L−1) is concentration of desorbed Ph or DNP. 2.6. 6. Removal of Ph and DND from wastewaters Two different wastewater samples named WT1 and WT2 were obtained from wastewater treatment plant located in Dong Anh district, Hanoi, Vietnam. The basic properties of wastewaters were characterized after primary treatment processes including screening and grit removal (see in Table 2). The wastewaters contained a high concentration of Ph (87.2 mg L−1) and DNP (108.1 mg L−1), along with others inorganic pollutants. To assess the applicability of the CBC in industrial wastewater, the removal of Ph and DNP were subsequently conducted as descried in section 2.4 (under optimized conditions of pH 7.0, adsorbent dosage of 0.3 g and contact time of 90 min).
3.2. Removal of Ph and DNP experiments 3.2.1. Effect of adsorbent dose and reaction time on the removal of Ph and DNP Fig. 2(a) showed the removal efficiencies of Ph and DNP by CBC as function of adsorbent dose. The removal efficiencies of Ph and DNP per unit weight of adsorbent rapidly increased with increasing dose of CBC to a maximum of 89.6 and 97.3% at 0.3 g, after which there was no appreciable change in the removal efficiencies of Ph and DNP. The increase in the removal efficiency of pollutant due to the availability of
Table 2 Properties of wastewater samples. Samples
COD (mg L−1)
TOC (mg L−1)
BOD (mg L−1)
pH
Ph (mg L−1)
DNP (mg L−1)
Cl− (mg L−1)
NO3− (mg L−1)
WT1 WT2
125.4 151.3
241.3 298.6
92.7 113.6
9.98 5.37
87.2 –
– 108.1
423 328.5
189.7 162.7
3
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Table 3 Elemental and surface area analysis. Pyrolysis condition
100 °C 200 °C 300 °C 400 °C 500 °C 600 °C
(under (under (under (under (under (under
air – oven) N2 gas – furnace) N2 gas – furnace) N2 gas – furnace) N2 gas – furnace) N2 gas – furnace)
BET surface area (m2 g−1)
Elemental composition (% wt.) C
O
H
N
Others
21.3 35.1 41.5 66.7 68.8 54.2
34.4 38.9 43.3 51.8 54.3 46.4
21.6 20.8 19.7 16.3 18.8 19.7
13.3 12.7 11.5 8.8 10.5 10.6
5.7 5.2 4.9 5.7 4.5 4.3
25.3 22.3 20.6 18.4 11.9 11.8
more number of binding sites or activated site on the adsorbents surface (Pan et al., 2016; Sun et al., 2019; Bardestani et al., 2019). Any further increase in adsorbent dosage did not contribute to any increase in removal efficiency of Ph and DNP. Based on the result, the adsorbent dose of 0.3 g was chosen as optimum dosage for further experiments. The equilibrium time of adsorption is important parameter to develop method for wastewater treatment in pilot-scales. The adsorption behavior of Ph and DNP by CBC as function of reaction time are presented in Fig. 2(b). It can be seen that, the removal of phenolic compounds increased with increasing reaction time from 10 to 60 min, then plateaued after the reaction reached equilibrium (at 90 min). The adsorption equilibrium was obtained at a reaction time of 90 min for Ph and DNP with removal efficiencies of 83.5 and 98.6%, respectively. The adsorption of Ph and DNP by CBC were very quick in the first 90 min of the experiment, while no significant changes were observed after that, implying that the adsorption process had already reached the equilibrium state at 90 min. This result might be due to the availability of a huge number of vacant sites saturated with time. As a rule of thumb, by increasing contact time the availability of adsorbate molecules to unoccupied active sites on the adsorbent surface decreases, and as a result, these sites are ultimately saturated when the process reaches the equilibrium state (Coleman et al., 2019; Kang et al., 2019; Jang and Kan, 2019). Hence, the optimal reaction time for the adsorption of Ph
and DNP using CBC were maintained at 90 min. 3.2.2. Adsorption kinetics The results of adsorption kinetic-related values for Ph and DNP using CBC are presented in Table 4 and Fig. S3 (supplementary information). It demonstrated that the correlation coefficient from FO (R2 < 0.65) was lower than that of SO model (R2 > 0.95), confirming that the experimental data obey the SO kinetic model. However, the qe,cal value of the SO model for Ph and DNP were 28.7 and 26.5 mg g−1, respectively, which were more close to the qe,exp value (around 29.1 mg g−1), suggesting that the SO model fitted well to describe the adsorption behavior of Ph and DNP onto CBC. This revealed that chemisorption is the dominant mechanism in the adsorption process, which involves short-range interactions of π–π and hydrogen bonding between functional groups of adsorbent and adsorbed. The results from adsorption kinetics of this work are in-line with those of previous works using biochar for removal of organic pollutants (Varjani et al., 2019; Kang et al., 2019). 3.2.3. Effect of initial concentration The effect of initial concentration on the removal of Ph and DNP using CBC was investigated and the results are showed in Fig. 3. As the initial concentration increase from 10 to 200 mg L−1, the removal
Fig. 1. SEM analysis. (a) and (b): Surface morphology of chicken manure biomass. (c) and (d): Surface morphology of chicken manure biochar. 4
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Fig. 2. (a). Effect of adsorbent dose on the removal of Ph and DNP. Fig. 2 (b). Effect of reaction time on the removal of Ph and DNP.
5
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in the initial concentration of pollutants also reduced the adsorption capacity due to impossible of surface area and activated on the surface of adsorbent (Kang et al., 2019; Oh and Seo, 2019).
Table 4 Adsorption kinetics parameters. First-order kinetic model −1
Adsorbed
qexp (mg g−1)
k1 (min
Ph DNP
29.3 29.1
0.10 0.05
)
Second-order kinetic model 2
qe, cal (mg g−1)
R
k2 (g (mg min)−1)
qexp (mg g−1)
R2
18.6 14.9
0.31 0.60
0.05 0.02
28.7 26.5
0.99 0.96
3.2.4. Adsorption isotherm The adsorption parameters and their data fitting of two adsorption isotherm models are given in Table S2. The plot of Langmuir isotherm model Ce/qe against Ce and the slope and intercept plot of log qe against log Ce for the Freundlich model are shown in Fig.S4 (a) and S4 (b), respectively. The values of maximum adsorption capacity (qmax), and KL corresponding to the R2 which were calculated by the Langmuir plots. The correlation coefficient (R2) of Ph and DNP from the Langmuir isotherm model were significantly higher (R2 ≥ 0.98) than that of the Freundlich model (R2 ≤ 0.40). The higher relative correlation coefficient of the Langmuir isotherm model indicated that it better described the phenolic adsorption on CBC. The result also investigated that the adsorption of Ph and DNP onto CBC followed the unilayer adsorptive mechanism with a homogenous distribution of active sites. This means that a monolayer of adsorbate was formed on the surface of adsorbent and no further adsorption occurs after complete coverage of the active surface. This model also is valid for monolayer adsorption onto a surface exhibiting a finite number of identical sites (Pham et al., 2016a, 2016b; Bardestani et al., 2019; Coleman et al., 2019). Based on the Langmuir isotherm, the maximum adsorption capacity of Ph and DNP were found to be 106.2 and 148.1 mg g−1, respectively. Recently, various alternative adsorbents produced from forest, agricultural byproducts have been used for adsorption of Ph and DNP from aqueous solution (see in Table 5). The biochar from bamboo biomass showed highest value of qmax for Ph (166.7 mg g−1), which was slightly higher than this study (106.2 mg g−1). The maximum adsorption capacity of Ph provided by other biochar such as pine fruit shell (26.7 mg g−1), rice straw (80.5 mg g−1), granulated cork (0.9 mg g−1), rice husk (14.4 mg g−1), coconut shell biochar (19.9 mg g−1) or even commercial activated carbon (69.9 mg g−1) were much lower than in this study. In addition, the removal of DNP using biochar as adsorbent was done by showed very low adsorption capacity of DNP (32.26 mg g−1) as compared to CBC (148.1 mg g−1). These results demonstrate the potential of the CBC as an alternative adsorbent for removal of Ph and DNP from water. Nevertheless, the other advantages include a simple production process,
Fig. 3. Effect of initial concentration on the removal of Ph and DNP.
efficiencies of Ph and DNP decreased from 98.8 to 80.5% and 98.2 to 81.7%, respectively. At low initial concentration, the surface area and activate site of CBC are available for the contribution as well as the improvement in the adsorption capacity of phenolic compounds (Varjani et al., 2019; Oh and Seo, 2016). The removal efficiency of Ph and DNP were declined at high initial concentration due to the competition of phenolic compounds molecules onto the limited surface or activated site of CBC. As previous reported by other studies, an increase
Table 5 Comparisons of maximum adsorption capacity for Ph and DNP by different biochar adsorbents. Adsorbents
Adsorbates
Conditions
qmax (mg g−1)
Mechanism
References
Mohammed et al. (2018) Yakout (2017) Mallek et al. (2018)
o
pH
Temp ( C)
Pine fruit shell (heat treatment 550 °C)
Ph
6.5
25
26.73
Rice straw (heat treatment 550 °C) Granulated cork (Without heat treatment) Rice husk (heat treatment 550 °C) Corn husk 500 °C Commercial activated carbon Coconut shell biochar 500 °C Bamboo biochar 550 °C Chemical modification of Kola nut CBC
Ph Ph
7.0 6.0
25 20
80.5 0.92
Dispersive interaction, electrostatic interaction and π-π interaction NA π-π interaction
Ph Ph
6.0 7.0
22 25
14.4 8.44
NA Electro-donor, π-π interaction
Tran et al. (2015) Mishra et al. (2019)
Ph Ph
5.0 7.0
20 25
69.95 19.94
Hydrophilicity interaction Van der Waals' force, π-π interaction
Sun et al. (2019) Hao et al. (2018)
Ph
6.0
20
166.72
NA
Jin et al., 2018
DNP Ph
7.0 7.0
25 22
32.26 106.2
CBC
DNP
7.0
22
148.1
Surface diffusion, pore diffusion and interior sites electrostatic interaction, hydrogen bonding and π-π interaction electrostatic interaction, hydrogen bonding and π-π interaction
6
This study This study
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deprotonated form (DNP−) when the pH = 7.0. The adsorbent surface charge and the deprotonated form of DNP adsorbate both suggest that stronger electrostatic interaction occurred between CBC and DNP as compared to Ph.
low-cost as compared to commercial activated carbon, the widespread availability of waste feedstock and concurrent waste management. This suggests that CBC can be a promising adsorbent for treatment of Ph and DNP in wastewater. The Freundlich isotherm is derived by assuming a heterogeneous surface with a non unifrom distribution of adsorption heat over the surface through a multilayer adsorption process. The constant KF is an approximate indicator of the adsorption capacity of Ph and DNP onto CBC. From Table S2, it can be seen that the KF values of Ph and DNP were 85.3 and 97.6 mg g-1, respectively. In spite of the lower correlation coefficients of the experimental data with Freundlich model by comparing to the Langmuir model, the same hierarchy of adsorption capacity was obtained: Ph < DNP. Moreover, the value of 1/n could be considered both a function of the strength of adsorption and heterogeneity parameter (if 1/n = 1, adsorption is linear; 1/n > 1, it is chemical and 1/n < 1, adsorption is physical favorable process). The heterogeneity factor (1/n) were 0.32 and 0.47 for Ph and DNP, respectively. The results suggested that adsorption of Ph and DNP onto CBC in favorable physics sorption and the Freundlich isotherm is a less appropriate isotherm than the Langmuir (Pham et al., 2016a, 2016b; Pan et al., 2019; Zeng et al., 2019).
3.2.7.2. The π-π interaction. Considering the π-bond interaction between the benzene ring of phenolic pollutants and the π electron distribution bonded to the CBC edges, the increase in the dispersive adsorption potential of the adsorbent surface increases the adsorption capacity on the CBC surface (Xing et al., 1994; Mishra et al., 2019; Zeng et al., 2019). In the π-π interaction, the oxygen-containing functional groups of CBC surface act as electron donors and the aromatic rings of phenolic pollutants act as electron acceptors (Yang and Xing, 2010). The surface functional groups of CBC such as –COOH and –OH play a certain role in the adsorbing phenolic pollutants (Heibati et al., 2014). The concept of the π-π interaction mechanism assumes charge transfer between the π electrons of the benzene ring and the π electron distribution bonded to the CBC surface, leading to the increase in the uptake capacity of Ph and DNP onto the adsorbent (Oh and Seo, 2016; Kang et al., 2019). Moreover, Coughlin and Ezra (1968) confirmed the π-π interaction between the π-electrons of the aromatic rings of an adsorbate and the π-electrons of a carbonaceous adsorbent. From Table 1, it can be seen that, the DNP molecule presented two polar nitro-functional group (as strong electron acceptors) on the benzene ring, leading to strong π-π interaction between CBC and DNP. Therefore, more adsorption capacity of DNP onto CBC is expected compared to that of Ph.
3.2.5. Regeneration Recovery of adsorbent is important process in order to evaluate the economical of adsorption process. The CBC showed high adsorption capacity and desorption efficiency for both of Ph and DNP (see in Fig. 4(a) and b). The desorption efficiencies of Ph and DNP were close to 100% for the first and the second cycles, then decreased by 31.3 and 23.6% at the fifth cycles, respectively. Besides, the CBC showed high adsorption capacities of Ph and DNP for the first three cycles and slightly decreased (less than 20%) after five repeated cycles. This high reusability, combined with facile regeneration characteristics and high adsorption capacity, demonstrated the potential use of the CBC as promising adsorbent for treatment of wastewater containing phenolic compounds (Oh and Seo, 2019; Varjani et al., 2019).
3.2.7.3. Hydrogen bond. Finally, the hydrogen bonding contributed as one of the strongest interaction mechanisms between CBC and phenolic compounds. The hydrogen bonding takes place by the sharing of electrons between CBC and adsorbate (Ph and DNP). Hydrogen bonding interactions can occur as follows: (a) between surface hydrogens of the hydroxyl groups (H-donor) on the CBC′ surface and the appropriate atoms (nitrogen and oxygen; H-acceptor) of phenolic, and (b) between the hydroxyl groups on the CBC′ surface and the aromatic rings in Ph and DNP molecules (Coughlin and Ezra, 1968; Heibati et al., 2014; Tran et al., 2017; Kang et al., 2019). Therefore, the surface hydroxyl groups such as –OH and –COOH of adsorbent interact with –OH and –NO2 groups of adsorbate to form hydrogen bonds at various positions, which enhances the adsorption capacity (Mishra et al., 2019; Zeng et al., 2019). In addition, the surface of the CBC has the point of zero charge (pHpzc) at around pH 7.11 ± 0.1 (Fig. S2). The point of zero charge can be defined as the suspension pH at which a surface has a net charge of zero. When the pH is lower than pHpzc, the surface of adsorbent has net positive charge and if the pH > pHpzc, the surface of adsorbent has net negative charge. On the other hand, the pKa values of Ph and DNP were 9.3 and 4.1, respectively. Under the neutral solution (pH = 7.0), the adsorption of DNP could be increased more than that for Ph due to its relatively greater negative charge. Moreover, the dipole moment of Ph (1.4D) is smaller than that of DNP (5.7D), leading that DNP can easily interact with the surface of CBC. In general, the dipole-dipole force interaction is considered as a rational adsorption mechanism (Xing et al., 1994; Oh and Seo, 2019). The larger dipole moment of DNP can increase the bonding with CBC, which then promotes a certain synergistic DNP adsorption capacity. This phenomenal was confirmed by the identified maximum adsorption capacity of DNP (148 0.1 mg g−1), which was much higher than that of Ph (106.g mg g−1).
3.2.6. Filed application in wastewaters Fig. 5 displayed the removal efficiency of Ph and DNP from wastewaters using CBC. The wastewater samples contain relatively high concentration of phenolic compounds and others different contaminants (Table 2). CBC showed excellent removal efficiencies for Ph and DNP at around 78.5 and 83.4%, respectively. Therefore, biochar derived from chicken manure can be successfully applied as low-cost adsorbent for removal of Ph and DNP in wastewater. 3.2.7. Adsorption mechanism Due to the lack of experimental and theoretical research and unavailable data on the Ph and DNP adsorption characteristics from solution using CBC, the development of a plausible description for the Ph and DNP adsorption mechanism will expand our understanding of the adsorbent-adsorbate interaction mechanisms. The Ph and DNP can be adsorbed easily onto the surface of CBC due to its high surface area, high porous structure and containing large oxygen surface functional groups (confirmed by SEM, BET and FTIR analysis). Fig. S5 shows the possible adsorption mechanisms of Ph and DNP onto CBC, which can be considered as the result of major mechanisms listed below: 3.2.7.1. Electrostatic interaction. Under the neutral solution (pH = 7.0) the surface of CBC is positively charged while the DNP and Ph are negatively charged because of the electron-rich benzene ring. Therefore, Ph and DNP will be attracted towards the positively charged CBC surface, resulting in the removal of Ph and DNP from the solution. Besides, the pKa values of Ph and DNP were 9.3 and 4.1, respectively, thus the Ph existed in neutral form and the DNP existed in
3.2.8. Practical applications and future research Water quality is a serious environmental problem presently faced by many countries or communities (Nguyen et al., 2016; Rene et al., 2018a, 2018b; Varjani et al., 2019). It is becoming a global challenge to 7
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Fig. 4. (a). Desorption efficiency of Ph and DNP. Fig. 4 (b). Desorption capacity of Ph and DNP.
ensure clean drinking water and clean up wastewater bodies contaminated by the causes of population growth, increased industrial activities, and frequent natural disasters (Ahmed et al., 2016; Antunes et al., 2017). A particularly important global issue is to develop more
efficient and cost-effective water treatment processes of organic pollutants in water. Phenol and 2,4-dinitrophenol are listed as priority pollutants due to their high toxicity and carcinogenicity properties. Therefore, the development technology which can completely remove 8
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Acknowledgements This work was supported by Duy Tan University. Appendix A. Supplementary data Supplementary data to this article can be found online at https:// doi.org/10.1016/j.jenvman.2019.109556. References Ahmed, M.B., Zhou, J.L., Ngo, H.H., Guo, W., Chen, M., 2016. Progress in the preparation and application of modified biochar for improved contaminant removal from water and wastewater. Bioresour. Technol. 214, 836–851. Antunes, E., Jacob, M.V., Brodie, G., Schneider, P.A., 2017. Silver removal from aqueous solution by biochar produced from biosolids via microwave pyrolysis. J. Environ. Manag. 203, 264–272. Bardestani, R., Roy, Ch, Kaliaguine, S., 2019. The effect of biochar mild air oxidation on the optimization of lead (II) adsorption. J. Environ. Manag. 240, 404–420. Coleman, B.S.L., Easton, Z.M., Bock, E.M., 2019. Biochar fails to enhance nutrient removal in woodchip bioreactor columns following saturation. J. Environ. Manag. 232, 490–498. Coughlin, R.W., Ezra, F.S., 1968. Role of surface acidity in the adsorption of organic pollutants on the surface of carbon. Environ. Sci. Technol. 2, 291–297. Das, B., Mandal, T.K., Patra, S., 2015. A comprehensive study on Chlorella pyrenoidosa for phenol degradation and its potential applicability as biodiesel feedstock and animal feed. Appl. Biochem. Biotechnol. 176, 1382–1401. Das, J., Rene, E.R., Krishnan, J., 2018. Photocatalytic degradation of volatile pollutants. J. Photocatalytic degradation of volatile pollutants. J. Environ Chem Toxicol. 2, 57–59. Do, X.H., Lee, B.K., 2015. Removal of Pb2+ using a biochar-alginate capsule in aqueous solution and capsule regeneration. J. Environ. Manag. 131, 375–382. Hao, Zh, Wang, C.H., yan, Z.Sh, Jiang, H.L., Xu, H.Ch, 2018. Magnetic particles modification of coconut shell-derived activated carbon and biochar for effective removal of phenol from water. Chemosphere 211, 962–969. Heibati, B., Rodriguez-Couto, S., Amrane, A., Rafatullah, M., Hawari, A., Al-Ghouti, M.A., 2014. Uptake of reactive black 5 by pumice and walnut activated carbon: chemistry and adsorption mechanisms. J. Ind. Eng. Chem. 20, 2939–2947. Jang, H.M., Kan, E., 2019. Engineered biochar from agricultural waste for removal of tetracycline in water. Bioresour. Technol. 284, 437–447. Jin, D.F., Xu, Y.Y., Zhang, M., Jung, Ok, Y.S., 2018. Comparative evaluation for sorption capacity of four carbonaceous sorbents to phenol. Chem. Spec. Bioavalab. 28, 18–25. Jung, J.M., Lee, R., Lee, J., Kee, T., Tsang, D.C.W., Kwon, E.E., 2017. Biodiesel synthesis using chicken manure biochar and waste cooking oil. Bioresour. Technol. 244, 810–815. Jung, M., Oh, J.I., Baek, K., Lee, J., Kwon, E.E., 2018. Biodiesel production from waste cooking oil using biochar derived from chicken manure as a porous media and catalyst. Energy Convers. Manag. 165, 628–633. Kang, S., Kim, G.Y., Choe, J.K., Choi, Y.J., 2019. Effect of using powdered biochar and surfactant on desorption and biodegradability of phenanthrene sorbent to biochar. J. Hazard Mater. 371, 253–260. Lee, J., Choi, D., Ok, Y.S., Lee, S.R., Kwon, E.E., 2017. Enhancement of energy recovery from chicken manure by pyrolysis in carbon dioxide. J. Clean. Prod. 164, 146–152. Mallek, M., Chtourou, M., Portillo, M., Monclus, H., Walha, K., Salah, A.B., Salvado, V., 2018. Granulated cork as biosorbent for the removal of phenol derivatives and emerging contaminants. J. Environ. Manag. 223, 576–585. Mishra, S.H., Yadav, S.S., Rawat, Sh, Singh, J., Koduru, J.R., 2019. Corn husk derived magnetized activated carbon for the removal of phenol and para-nitrophenol from aqueous solution: interaction mechanism, insights on adsorbent characteristics, and isothermal, kinetic and thermodynamic properties. J. Environ. Manag. 246, 362–372. Mohammed, N.A.S., Abu-Zurayk, R.A., Hamadneh, I., Al-Dujaili, A.H., 2018. Phenol adsorption on biochar prepared from the pine fruit shells: equilibrium, kinetic and thermodynamics studies. J. Environ. Manag. 226, 377–385. Nguyen, M.V., Lee, B.K., 2016. A novel removal of CO2 using nitrogen doped biochar beads as a green adsorbent. Process Saf. Environ. Prot. 104, 490–498. Nguyen, T.T., Thanh, B.X., Nguyen, D.D., Dan, N.P., Ngo, H.H., Guo, W., 2016. Performance and membrane fouling of two types of laboratory-scale submerged membrane bioreactors for hospital wastewater treatment at low flux condition. Separ. Purif. Technol. 165, 123–129. Oh, S.Y., Seo, Y.D., 2016. Sorption of halogenated phenols and pharmaceuticals to biochar: affecting factors a mechanism. Environ. Sci. Pollut. Res. 23, 951–961. Oh, S.K., Seo, Y.D., 2019. Factors affecting the sorption of halogenated phenols onto polymer biomass-derived biochar: effects of pH, hydrophobicity, and deprotonation. J. Environ. Manag. 232, 145–152. Pan, Y., Li, Z., Zhang, Z., Tong, X.S., Li, H., Jia, C.Z., Liu, B., Sun, C.Y., Yang, L.Y., Chen, G.J., 2016. Adsorptive removal of phenol from aqueous solution with zeolitic imidazolate framework-67. J. Environ. Manag. 169, 167–173. Pan, J., Ma, J., Liu, X.X., Zhai, L., Quyang, X.H., Liu, H.B., 2019. Effects of different types of biochar on the anaerobic digestion of chicken manure. Bioresour. Technol. 275, 258–265. Pham, T.H., Lee, B.K., Kim, J.T., Lee, C.H., 2016a. Nitrophenols removal from aqueous medium using Fe-nano mesoporous zeolite. Mater. Des. 101, 210–217. Pham, T.H., Lee, B.K., Kim, J.T., Lee, C.H., Chong, M.N., 2016b. Acid activation pine cone
Fig. 5. Removal of Ph and DNP from wastewaters.
Ph and DNP is needed. The production of biochar from agricultural wastes (chicken manure) in Vietnam showed high removal efficiency of Ph and DNP from industrial wastewaters. The low-cost of adsorbent, simple operation process for wastewater treatment along with no generation of by-products which can support CBC as a promising adsorbent for treatment of organic pollutants in wastewater. The results from this study could guide future research on development of biochar from agricultural wastes in Vietnam. A huge amount of agricultural wastes is directly effect to the environmental sustainability, thus converting wastes into add-value material like biochar could be an option for solid waste management as well as economic potential. The prices of biochar can be significantly lower than the prices of commercial activated carbon, leading to reduce operation cost for the wastewater treatment. However, it needs improve the research to some extent in the view which are listed below: 1. To develop the method for productions of biochar from other wastes in Vietnam such as coffee husk, rice husk, coconut shell and poultry litters. 2. To develop the modification method of biochar to improve the removal efficiency of organic pollutants. 3. To investigate the potential application of CB for removal of inorganic pollutants and nutrient form wastewaters. 4. To develop the pilot –scale for treatment of organic pollutants and so far can improve the quality of biochar in order to replace of expensive commercial activated carbon. 5. To extend the application of biochar for improving the soil quality. 4. Conclusions This study investigated the potential of biochar derived from chicken manure towards toxic phenol and 2,4-dinitrophenol in wastewaters. The CBC exhibited higher adsorption capacities for Ph and DNP than other previously reported materials. CBC also showed an excellent removal efficiency of Ph and DNP from real wastewaters along with high stability up to five cycles. The results collectively indicate that CBC could be used as a promising low-cost, recyclable adsorbent for treatment of organic pollutants in wastewaters. Conflict of interests The authors do not have any conflict of interests to declare. 9
Journal of Environmental Management 251 (2019) 109556
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