Adsorption and thermodynamic mechanisms of manganese removal from aqueous media by biowaste-derived biochars

Accepted Manuscript Adsorption and thermodynamic mechanisms of manganese removal from aqueous media by biowaste-derived biochars

Muhammad Idrees, Saima Batool, Hidayat Ullah, Qaiser Hussain, Mohammad I. Al-Wabel, Mahtab Ahmad, Amjad Hussain, Muhammad Riaz, Yong Sik Ok, Jie Kong PII: DOI: Reference:

S0167-7322(18)32185-8 doi:10.1016/j.molliq.2018.06.049 MOLLIQ 9247

To appear in:

Journal of Molecular Liquids

Received date: Revised date: Accepted date:

25 April 2018 9 June 2018 12 June 2018

Please cite this article as: Muhammad Idrees, Saima Batool, Hidayat Ullah, Qaiser Hussain, Mohammad I. Al-Wabel, Mahtab Ahmad, Amjad Hussain, Muhammad Riaz, Yong Sik Ok, Jie Kong , Adsorption and thermodynamic mechanisms of manganese removal from aqueous media by biowaste-derived biochars. Molliq (2017), doi:10.1016/ j.molliq.2018.06.049

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ACCEPTED MANUSCRIPT Adsorption and Thermodynamic Mechanisms of Manganese Removal from Aqueous Media by Biowaste-derived Biochars Muhammad Idreesa,b,*, Saima Batoola,b,

Hidayat Ullahb, Qaiser Hussainc,d,*, Mohammad I.

Al-Wabelc, Mahtab Ahmade, Amjad Hussainf, Muhammad Riazg, Yong Sik Ok h, Jie Konga a

MOE Key Laboratory of Space Applied Physics and Chemistry, Shaanxi Key Laboratory of

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Macromolecular Science and Technology, School of Natural & Applied Sciences,

Sciences Department, College of Food & Agricultural Sciences, King Saud University, P.O.

Box 2460, Riyadh 11451, Saudi Arabia d

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c

Institute of Chemical Sciences, Gomal University, Dera Ismail Khan 29220, Pakistan

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b

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Northwestern Polytechnical University, Xi’an, 710072, P. R. China

Department of Soil Science & Soil Water Conservation, PMAS Arid Agriculture University,

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Rawalpindi 46300, Pakistan e

Department of Environmental Sciences, Faculty of Biological Sciences, Quaid-i-Azam

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University Islamabad 45320, Pakistan f

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Research and Development Department, Higher Education Commission Islamabad, Pakistan

g

Department of Environmental Sciences & Engineering, Government College University

h

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Faisalabad, Pakistan

Korea Biochar Research Center, Divison of Environmental Science and Ecological

*

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Engineering Korea University, Seoul, Korea Corresponding

Authors,

E-mail

address:

[email protected]

(Q.H.);

[email protected] (M.I.) and, Tel.(fax): Tel.: +966-11-4679933; fax: +966-11467844

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ACCEPTED MANUSCRIPT Abstract In the present investigation, poultry manure and farmyard manure-derived biochars were applied as cost-effective adsorbents for manganese (Mn) removal from aqueous media. Effects of functional parameters such as solution pH, contact time, temperature and

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concentration on the Mn removal efficiency of biochars were evaluated. Poultry manurederived biochar exhibited greater adsorption efficiency than farmyard manure-derived

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biochar due to its porosity and surface functionality. The maximum adsorption was achieved

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at pH 6, temperature 298 K and contact time of 3 h. The adsorption isotherm data was well fitted to the Freundlich model indicating multilayer adsorption onto heterogeneous surfaces

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of the biochars. Thermodynamics calculations affirmed that Mn adsorption onto biochars was

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spontaneous and exothermic process governed by hydrogen bonding type of electrostatic interaction. Post-adsorption spectroscopic analysis of Mn-loaded biochars evidenced the binding of Mn with active surface functionalities of biochars.

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Keywords: Sorption; Manure; Char; Water treatment; Equilibrium

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ACCEPTED MANUSCRIPT 1.

Introduction Heavy metals enter into the environment through natural and anthropogenic sources.

The anthropogenic emission of heavy metals into the environment is deteriorating largely the soil and water resources (Idrees et al., 2016). Manganese (Mn) is the second most abundant among these heavy metals in nature. It has been considered as an essential micronutrient for

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plants and animals’ growth. However, at high concentrations, Mn becomes toxic to humans

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causing the Parkinson illness, pulmonary track disorder, bronchitis, and hindering the

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intellectual development and normal growth of infants (Anguille et al., 2013). Drinking water, including groundwater and surface water, is one of the main sources of Mn toxicity in

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humans. The world health organization (WHO) has established a safe drinking water concentration of 0.05 mg L-1 for Mn. Relatively less attention has been given to Mn removal

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from water because of its importance as an essential micronutrient. However, it is reported that continuous administration of Mn may increase the neurotoxicity risk in humans

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(Crossgrove et al., 2004).

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Various water treatment techniques are in practice, particularly focusing on heavy metals removal, such as adsorption, coagulation-flocculation, chemical precipitation, ion-

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exchange, electrocoagulation, etc. (Fu et al., 2011). Among these techniques, adsorption has been shown to be the simplest, economical and efficient technique of removing heavy metals

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from aqueous media (Emadi et al., 2012). Different types of materials including carbonaceous materials (activated carbon, charcoal, carbon-nano-tubes), clay minerals, synthetic polymers, activated alumina, and silica gel have been successfully applied as adsorbents for metals removal (Zhao et al., 2015; Meng et al., 2015; Chen et al., 2016). Increasing global demand of efficient adsorbents has resulted in their cost elevation; hence there is a surge of interest in developing the alternative low-cost adsorbents capable of removing heavy metals from aqueous solution (Kurniawan et al., 2013).

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ACCEPTED MANUSCRIPT Biochar, a carbon-rich material obtained from thermal decomposition of organic waste, has recently gained popularity as a universal and environmental green sorbent for organic and inorganic contaminants removal from water. Biochar has also shown its potential for mitigating climate change, carbon sequestration, soil quality improvement, enhanced crop production, and environmental management of waste recycling (Lehmann et al., 2009).

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Specifically, during the last years, biochar has proved its tendency of removing heavy metals

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such as cadmium and copper from water (Idrees et al., 2018; Batool et al., 2017). However, to

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our knowledge, no study has yet been conducted on removal of Mn from water using biochar. High surface area, the presence of numerous surface functional groups, and microporous

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structure are the distinguishing characteristics of biochar making it an efficient adsorbent for metals removal from water. Additionally, biochar is ~ 6 times cheaper than the most widely

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used activated carbon, thus fascinating it as a low-cost sorbent too (Aad et al., 2014). Manure waste is widely used as organic soil amendment. However, there are several

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environmental issues related to manure waste such as odor, methane production, and

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eutrophication of groundwater. Pyrolyzing the manure waste into biochar could provide an alternative waste management technology, thereby reducing the associated environmental

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issues of manure application to soil. The present study aimed at (1) conversion of poultry and farmyard manure into biochar, (2) assessment of manure-derived biochar for Mn removal

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from water, and (3) prediction of sorption phenomenon of Mn onto two different biochars.

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ACCEPTED MANUSCRIPT 2.

Materials and Methods

2.1.

Chemical reagents The chemical reagents used were of analytical grade. The deionized water of 18

MΩ.cm resistivities was used for solutions preparation. Manganese sulfate (MnSO4.H2O), sulfuric acid (H2SO4) and sodium hydroxide (NaOH) were purchased from Sigma. A stock

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solution of 1000 mg Mn L-1 was prepared in deionized water, and further working solutions

2.2.

Biochar production and characterization

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of desired strength were prepared by diluting the stock solution in deionized water.

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Poultry manure and farmyard manure were selected as feedstock for the production of biochar (BC). Poultry manure and farmyard manure samples were collected from the poultry

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farm and livestock farm of the University campus, respectively. The manure samples were oven-dried at 60 °C. The oven-dried manure samples were packed in the ceramic container

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covered with a lid and then placed in a muffle furnace at 450 °C for 5 h under oxygen-limited

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condition. After the pyrolysis, containers were taken out of the furnace and allowed to cool at room temperature. Finally, the poultry manure-derived BC (PBC) and farmyard manure-

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derived BC (FBC) were passed through the 0.18 mm sieve to get the uniform particle size. The BCs’ surface structural morphology was analyzed by scanning electron

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microscopy (SEM; INCAX-ACT, 58794; Oxford Instruments, China), while their surface functionality was identified by Fourier transform infrared (FTIR) spectroscopy (PerkinElmer, USA). The thermal transformation of the prepared BCs’ was determined by a thermogravimetric analyzer (TGA; NETZSCH STA449F3, Germany) with a heating rate of 10 ºC min-1 within 40-1000 ºC in Argon. The surface electronic structure of BCs’ was checked by X-ray photoelectron spectroscopy. Elemental (C, H, and N) analyses were performed using a CHN elemental analyzer (Perkin Elmer, USA), while the surface area of

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ACCEPTED MANUSCRIPT BCs’ was determined via N2 adsorption on a BET Surface Area Analyzer (Gemini VII 2390 Series-Micromeritics, USA). The pH of BCs was determined using a pH meter (Mettler Toledo Delta 320) in a suspension of 1:10 BC/deionized water after 1 h shaking. Ash contents of BCs were determined by combusting the oven-dried samples at 700 °C for 2 h in

Sorption equilibrium experiment

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2.3.

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open top ceramic crucibles.

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To test the capability of manure-derived BCs as sorbents, batch type sorption equilibrium experiments were carried out with aqueous Mn solutions. A sorbent dose of 10 g

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L-1 was applied to each Mn solution of initial concentration ranging from 2 to 50 mg L-1. The pH of solutions was adjusted between 2 to 6 with 1N NaOH and H2SO4 solutions. The

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mixtures were equilibrated on an incubator shaker (MSC-100, China) for 24 hours at 180 rpm. To determine the effect of temperature on Mn sorption onto BCs, the sorption

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experiments were conducted at three different temperatures of 298, 308 and 318 K at a fixed

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pH of 4. After equilibrium time of 24 h, the suspensions were filtered through Whatman 42 filter paper, and the solution was analyzed for Mn concentration on an atomic absorption

2.4.

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out in triplicate.

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spectrometer (AAS, Perkin-Elmer 214, Norwalk, CT). All the batch experiments were carried

Sorption isotherms The retention of Mn on manure-derived BCs was investigated by drawing the sorption

isotherms between Mn concentration at equilibrium and amount of Mn sorbed onto the BCs. The sorbed amount of Mn was calculated using the following (Eq. (1)) (Limousin et al., 2007):

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ACCEPTED MANUSCRIPT Qe =

V m

(C0 − Ce )

(1)

where Qe is the amount of Mn sorbed onto BCs (mg g-1) at equilibrium, V is the volume of solution (L), C0 is the initial Mn concentration (mg L-1), Ce is the Mn concentration at equilibrium (mg L-1), and m is the mass of sorbent (g). The isotherm data was then subjected

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to the most widely used empirical models of Freundlich, Langmuir, and Temkin, the

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linearized forms are presented in (Eqs. (2), (3) and (4), respectively.

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m

Qe = B=

RT b

1

]

1

L Qm C e

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1

= Q + [K

ln(ACe )

RT

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1 Qe

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lnQe = lnK F + n lnCe

b

(2) (3) (4) (4a)

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where KF is the Freundlich constant [(mg g-1) (L g-1)n], n is a dimensionless constant, Qm is the Langmuir maximum adsorption capacity (mg g-1), KL is the Langmuir affinity constant (L mg-1), R is the universal gas constant (8.314 J mol-1), T is the temperature (K), b is the

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Temkin isotherm constant, B is the heat of sorption (J mol-1), and A is the Temkin

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equilibrium binding constant (L g-1). The removal efficiency of each BC for Mn was calculated using the following (Eq. (5)):

Removal efficiency (%) = [

2.5.

C0 −Ce C0

] × 100

(5)

Sorption kinetics experiment To evaluate the sorption rate of Mn on manure-derived BCs, batch type sorption

kinetics experiments were performed. The aqueous Mn solution of 50 mg L-1 initial 7

ACCEPTED MANUSCRIPT concentration was mixed with each BC at a rate of 10 g L-1. The mixtures were shaken on an incubator shaker at 180 rpm. Samples were withdrawn after 1, 2, 3, 4, 5, and 6 h, filtered through Whatman 42 filter paper and analyzed for aqueous Mn concentration by using AAS. The kinetics sorption experiments were conducted at two different temperatures of 308 and

V m

(C0 − Ct )

(6)

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Qt =

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different time intervals was calculated following the (Eq. (6)).

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318 K. All the batch experiments were carried out in triplicate. The amount of Mn sorbed at

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where Qt is the amount of Mn sorbed (mg g-1) onto BCs at time t (h), and Ct is the remaining

described in section 2.4. 2.6.

Thermodynamics calculations

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Mn concentration (mg L-1) in aqueous solution at time t. The V, m, and C0 have already been

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To determine the effect of temperature on Mn sorption on manure-derived BCs,

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Gibb’s free energy change (ΔG0), enthalpy change (ΔH0), and entropy change (ΔS0) were calculated. The apparent equilibrium constant (K) is given by the following (Eq. (7)) (Zhou et

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al. 2014):

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K = K nF × M × 1000 × 55.5

(7)

where M is the molecular weight of Mn (54.94 g mol-1), and 55.5 is the molar concentration of water. The obtained value of K was then used into the (Eq. (8)) to calculate the ΔGo.

∆G0 = −RT lnK

(8)

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ACCEPTED MANUSCRIPT where R is the universal gas constant (8.314 J mol-1 K-1), and T is the temperature (K). The values of ΔH0 and ΔS0 were respectively obtained from the slope and intercept of the plot between lnK and 1/T (van’t Hoff plot) by considering the following (Eqs. (9) and (10)): ∆Go = ∆H o − T∆S o R

(T) +

∆So

(10)

R

Statistical analysis

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2.7.

∆Ho 1

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lnK = −

(9)

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An average of three replicates from each batch experiment was employed to plot sorption equilibrium and kinetics isotherms. Linear regression fittings were used for

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empirical and kinetic model equations. Slope and intercept values were used to calculate

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different models parameters.

The standard errors of the mean were calculated for the experimental data interpretation in all

Results and discussion

3.1.

Biochar characteristics

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3.

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batch type sorption experiments shown in the Table S1.

The FBC had high pH (8.2), total carbon (47.47%) and surface area (10.11 m2 g-1),

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and fewer ash contents (27.18%) than PBC. Relatively low surface area of PBC (8.61 m2 g-1)

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compared to FBC was attributed to its high ash contents (31.44%). In fact, high ash contents could fill and block the micropores of biochar, resulting in a relatively low surface area (Idrees et al., 2018).

The FTIR spectral analysis predicted several functional groups on the surfaces of manure-derived BCs (Fig. 1a&b). The wave numbers 3399.66 cm-1 and 3377.92 cm-1 for FBC and PBC, respectively, were assigned to O-H stretching vibrations, while the bands from 2955.68 to 2510.86 cm-1 indicated the C-H aliphatic stretching vibration. The band numbers (1418.06 cm-1, 1432.27 cm-1), (1090.30 cm-1 - 1031.77 cm-1) and (798.49 cm-1 9

ACCEPTED MANUSCRIPT 565.21 cm-1) in both the BCs could be attributed to CO3-2, C-O and aromatic C-H groups, respectively. The bands at 1592.80 cm-1 in FBC and 1585.28 cm-1in PBC were assigned to C=O stretching of conjugated ketones and quinones. The bands at 1418.06 cm-1 and 1432 cm1

for FBC and PBC, respectively, represented the aromatic C=C stretching, while the band at

798.49 cm-1 in both BCs indicated out-of-plane deformation by aromatic C-H groups that

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might be caused by carbonates. The sharp peaks at 1031.77 cm-1 were assigned to phosphate

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(PO43-) in both the BCs spectra. The presence of aromatic C shows the stability of BC while

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aliphatic C may indicate the labile component of BC (Purakayastha et al., 2015). The Fig. 2 shows the SEM images of FBC and PBC. A tessellated carbon surface is

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seen in crater-like structures. Pores and channels were formed in both the BCs owing to the removal of volatiles during pyrolysis at 450 ºC. Nevertheless, it should be noted that

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structural features in the heterogeneous range were observed in both these BCs. The TGA curves of FBC and PBC are presented in Fig. 3(c). The curves indicate

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weight loss with increasing temperature. Greater weight loss was observed for PBC, which

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predicted its less stability than FBC. Generally, poultry manure contains greater contents of organic matter than farmyard manure causing its less thermal stability (Kong et al. 2011).

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Specifically, a sharp weight loss in FBC was observed at 750 – 800 ºC corresponding to the decomposition of CO3-2 to CO2

(Lim et al. 2013), whereas no sharp weight loss was

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observed for PBC. These results are consistent with the FTIR results showing a more intense band of CO3-2 in FBC (1418 cm-1) than PBC (1432 cm-1) (Fig. 1a&b). The surface elemental composition of the BCs was analyzed by XPS. For both the BCs, it could be seen that the main peaks at binding energies of 283.58 eV and 530.22 eV were attributed to the C and O atoms, respectively (Fig. 3 a). Moreover, compared to FBC, the intensity of C and O peaks was more in case of PBC, indicating the relatively high

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ACCEPTED MANUSCRIPT proportion of these atoms on the surface of PBC. A short peak at a binding energy of 99.25 eV of Si appeared in PBC, while it was absent in FBC.

3.2.

Effects of pH, temperature and initial metal ion concentration on Mn removal efficiency of BCs

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The acidity of solution (pH) is one of the important parameters that affect the

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adsorbent surface charge, degree of ionization and speciation of the metal ions in solution.

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Mn adsorption onto FBC and PBC was carried out at varying range of pH (2.0, 4.0 and 6.0), an adsorbent dose of 0.25 g, contact time of 24 h, 180 rpm shaking speed and adsorbate

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concentration of 50 mg L-1. Results indicated that Mn removal efficiency increased with increasing solution pH (Fig. 4a), regardless of BC type. High removal efficiency (> 80%) at

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less acidic pH could be attributed to low H+ ion concentration, providing less competition with Mn2+ for adsorption onto negatively charged surfaces of BCs (Ahmad et al., 2016). In

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other words, an excess of H+ ions at low pH of 2.0 and 4.0 surround the binding sites of BCs,

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thus making sorption relatively unfavorable. The Fig. 4b shows that higher temperature did not favor the Mn adsorption; rather it

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decreased the adsorption onto BCs. This could be due to the reason that higher temperature leads to the higher kinetic energy of the Mn2+ ions, therefore weakening the forces of

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attraction between the Mn2+ ions and the BCs. This also indicated that the process was exothermic. The similar decreasing trend of Mn removal efficiency with increasing temperature was observed for both the BCs, and no significant difference in removal efficiencies was noted for FBC and PBC. Initial metal ion concentration gives an impelling cause to overcome all metal transfer resistances in the solid and aqueous media and this leads to a collision of higher probability between the active sites of BCs and Mn. The adsorption sites at some point of time become

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ACCEPTED MANUSCRIPT exhausted and reach a constant value where further adsorption from aqueous solution is not possible. Following these principles, Mn removal efficiency decreased with increasing initial concentration, in this study (Fig. 4 c&d). At an initial Mn concentration of 2 mg L-1, the removal efficiency ranged from 59.25% to 85.5% for FBC and 59.5% to 91.5% for PBC at different temperatures, while at 50 mg L-1 of Mn initial concentration the removal efficiencies

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were 47.82% to 69.95% and 40.26% to 70.58% for FBC and PBC, respectively. Temperature

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showed a significant effect on Mn removal efficiency at different initial metal ion concentrations (Fig. 4 c&d). Low temperature (298 K) favored the Mn sorption onto both the

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BCs. Specifically, at 298 K and very low initial concentration of 2 mg Mn L-1, the Mn

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removal efficiency was 85.5% and 91.5% for FBC and PBC, respectively, while at 318 K and high initial concentration of 50 mg Mn L-1, the Mn removal efficiency decreased to 47.82%

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and 40.26% for FBC and PBC, respectively. The decrease in Mn removal efficiency with increasing temperature may be due to the weakening of electrostatic forces between BC

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active sites and metal ion causing desorption from the interphase to the solution (Saltali et

3.3.

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al., 2007).

Adsorption isotherms

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The equilibrium adsorption isotherm data were subjected to linear forms of the Freundlich, Langmuir and Temkin models. The calculated constant parameters and

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correlation coefficients of each isotherm model are presented in Table 1. Based on the correlation coefficient (R2) values, the Freundlich and Langmuir models well described the equilibrium adsorption data (Fig. 5). Freundlich model was the adequate model fitting to the adsorption data at all the temperatures. The n value, representing the adsorption intensity, was more than 1 in both adsorbents and at all the temperatures, which indicated beneficial adsorption of Mn (Naiya et al., 2009). The KF values were higher at 298 K (0.520 mg g-1 for FBC and 1.103 mg g-1for PBC) and gradually decreased with increasing temperature. This

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ACCEPTED MANUSCRIPT indicated that the relative adsorption capacity of PBC was higher than FBC at 298 K. The Langmuir predicted maximum adsorption capacity (Qm) was also high at 298 K for FBC (6.652 mg g-1) than other temperatures. Likewise, the heat of sorption (B) values, calculated from Temkin model, were also low at low temperature and gradually increased with increasing temperature in both the BCs. This implied greater adsorption of Mn onto BCs at

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298 K as the heat of adsorption decreases with coverage (Foo et al. 2010).

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Overall, the Mn adsorption data followed the Freundlich isotherm model favorably at

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all the temperatures, indicating heterogeneity of the BCs and multilayer adsorption system. The maximum adsorption capacities of BCs in this study were compared with other

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carbonaceous adsorbents (Table 2). The adsorption capacities of BCs reported in this study are comparable with other adsorbents (Rachel et al. 2015). This makes the BCs derived from

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manure as cost-effective adsorbents since no activation or modification steps were involved, unlike other activated carbons. Effect of contact time

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3.4.

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Contact time is another important factor affecting the removal of metal ions in aqueous solution. The effect of contact time on Mn adsorption is shown in Fig. 6(a). The

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results showed that in the first hour Mn adsorption was very rapid, and after which the removal rate of Mn slowed down and attained equilibrium as adsorption time increases up to

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6 h. In general, maximum Mn adsorption was achieved within first 3 h. Temperature showed a negative effect on Mn adsorption, similar to as observed in adsorption isotherm experiments. Low temperature (308 K) was more favorable for Mn adsorption onto BCs at all the contact time intervals. No significant difference in sorption of Mn was observed at 308 K by both the BCs (FBC and PBC). However, at 318 K, PBC performed slightly better than FBC in Mn sorption, particularly after 3 h of contact time. Rapid adsorption within 1 h of contact time indicated the fast rate of reaction between BC active surfaces and Mn ions,

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ACCEPTED MANUSCRIPT which is owed to the high availability of free reactive sites on BC surfaces (Anagho Gabche et al., 2013). The PBC showed significantly high Mn sorption (2.460 ± 0.006 mg g-1 at 308 K and 2.146 ± 0.002 mg g-1 at 318 K) than FBC (2.304 ± 0.001 mg g-1 at 308 K and 2.018 ± 0.001 mg g-1 at 318 K) after one hour of contact time. The relatively high reaction rate of PBC could be related to its high O contents (as indicated by XPS data in Fig. 3a), which may

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have resulted in the deposition of Mn as MnO2 onto the surface of PBC (Contreras-Bustos et

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al, 2017).

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Achieving the sorption equilibrium in short contact time indicates the efficiency of the material. In wastewater treatment facilities, short contact time is favored because less

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operational time will enhance the process efficiency and minimize the operational cost of metal removal (Shafiq et al., 2018). Therefore, the BCs used in this study could serve as low-

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cost adsorbents for Mn removal from water. The fast initial sorption rate also suggests the high reactivity between sorbent and sorbate, which consequently determines the interaction

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between metal ions and active surface groups of the adsorbent material. Moreover, it implies

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that chemical adsorption could be dominant than physical adsorption taking less time of reaction (Li et al., 2009).

Thermodynamic studies

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3.5.

The results of calculated thermodynamic parameters for Mn adsorption onto BCs are

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shown in Fig. 6(b) and Table 3. Negative values of ΔGo and ΔHo indicated that the adsorption process is spontaneous and exothermic in nature, respectively. Likewise, the negative ΔSo values indicated that the adsorption process is favorable for both BCs without causing a structural change at the solid-liquid interphase (Tavlieva et al., 2015). A direct proportion was observed between ΔGo and temperature, demonstrating favorable adsorption at low temperature (Han et al., 2009). Mechanistic assumptions can be made from the ΔGo values. If ΔGo is 4 – 10 kJ

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ACCEPTED MANUSCRIPT mol-1, the dominant interaction is van der Waals force; for 2 – 40 kJ mol-1, hydrogen bonding is dominant; for 2 –29 kJ mol-1, dipole force of interaction is operable; for > 60 kJ mol-1, the chemical bonding is the main force of interaction (Huang et al., 2007). In this study, the ΔGo values range from -32.61 to -37.44 kJ mol-1, predicting that hydrogen bonding could be the dominant interactive force between Mn ions and BCs. Post-adsorption analyses

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Changes in the structural surface chemistry of BCs after Mn adsorption were

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determined by FTIR and XPS spectroscopic analyses to validate the adsorption phenomenon. The FTIR spectra of Mn loaded BCs were distinguishable from the original BC spectra (Fig.

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1c&d). The –OH band at 3399.66 cm-1 in FBC shifted towards 3436 cm-1in Mn-loaded FBC indicating the binding of –OH with Mn. Similar band shifting was also observed in PBC

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where the –OH band became sharp owing to bonding with Mn. The band associated with CO32- at 1418 cm-1 and 1432 cm-1 also shifted to 1429 cm-1 and 1606 cm-1 in FBC and PBC

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spectra, respectively, assuming due to Mn-carbonate formation. The PO43- band at 1032 cm-1

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in both the BCs became less intense, and shifted to 1076 cm-1 and 1062 cm-1 in FBC and PBC, respectively, which evidenced the formation of stable Mn-phosphate.

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XPS spectra of Mn loaded BCs are shown in Fig. 3 (b). Compared to the original XPS spectra of BCs, a new peak at 640.56 eV was observed for Mn 2p region, which shows

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different binding energies when combined with oxygen. Metallic Mn shows 638.7 eV binding energy and when combined with oxygen the binding energy is shifted up to 640.56 eV depending on the oxidation state of oxygen. It can be noted that in Mn-loaded BCs, the main peak appearing at 640.56 eV confirmed the formation of Mn2O3 (Chen et al., 2016). The post adsorption spectral analyses of Mn-loaded BCs predicted the formation of Mn compounds probably with carbonates and phosphates. These results are consistent with

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ACCEPTED MANUSCRIPT the adsorption kinetics data fitting to the pseudo-second-order model, prevailing chemisorption as the main phenomenon of Mn adsorption onto BCs. 4. Conclusions The present study evaluated the poultry manure- and farmyard manure-derived BCs as viable, and cost-effective adsorbents for the removal of Mn from aqueous media. The

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results revealed that the sorption was dependent on different functional parameters such as

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pH, temperature, contact time and concentration. The maximum adsorption was achieved at

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pH 6, temperature 298 K and contact time of 3 h. The adsorption isotherms were well fitted to the Freundlich model. The thermodynamic parameters from the experimental model

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presented that adsorption process was exothermic and spontaneous, involving hydrogen bond type interaction between Mn ions and BC surfaces. Post adsorption spectroscopic analyses

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predicted changes in the surface structural chemistry of the BCs as a result of Mn bonding with O-containing functional groups. The manure-derived BCs, therefore, could potentially

Acknowledgment

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be applied as efficient adsorbents for Mn removal from aqueous solutions.

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The authors extend their appreciation to the Deanship of Scientific Research at King Saud University for funding this work through research group No (RG- 1439-043). The authors are

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thankful to Analytical and Testing Center of NPU, Northwestern Polytechnical University, Xi’an 710072 P.R. China and Laboratory of Soil Science & Soil Water Conservation, PMAS Arid Agriculture University, Rawalpindi, Pakistan for providing research opportunities, analysis and characterization of the sorbents. Chinese Scholarship Council (CSC No: 2015GXZ039) financial support is gratefully acknowledged to pursuing Ph.D. studies. Conflicts of interest There are no conflicts to declare.

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ACCEPTED MANUSCRIPT References Aad, G., Abajyan, T., Abbott, B., Abdallah, V.J., Khalek, S.A., Abdinov, O., Abramowicz, H., 2014. Electron reconstruction and identification efficiency measurements with the ATLAS detector using the 2011 LHC proton–proton collision data. The European Ph,. J., C 74.7: 1-38. Ahmad, M., Lee, S.S., Lee, S.E., Al-Wabel, M.I., Tsang, D.C.W., Ok Y.S., 2016. Biochar

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induced changes in soil properties affected immobilization/mobilization of metals/metalloids in contaminated soils. J. Soils and Sediments 11368-015-1339-4.

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Akl, M.A., Yousef, A.M., AbdElnasser, S., 2013. Removal of iron and manganese in water

SC

samples using activated carbon derived from local agro-residues, Chem. Eng. Process Technol. 4, 154.

NU

Anagho Gabche, S., TchuifonTchuifon, D.R., NcheNdifor-Angwafor, G., NdiNsami, J., 2013. Nickel Adsorption from Aqueous Solution onto Kaolinite and Metakaolinite:

MA

Kinetic and equilibrium studies. Intern. J. Chem,. 4: 1-235. Anguille, J.J., Ona Mbega, G. M., Makani T. Ketcha Mbadcam, J., 2013. Adsorption of Manganese (II) ions from aqueous solution on to Volcanic Ash and Geopolymer

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D

based Volcanic Ash. Intern. J. Basic and Appl. Chem. Sci., 3: 7-18. Batool, S., Idrees, M., Hussain, Q., Kong, J., 2017. Adsorption of copper (II) by using derived-farmyard and poultry manure biochars: Efficiency and mechanism. Chem.

CE

Phys. Lett. 689, 190-198.

Chen, F., Zhao, W., Zhang, J., Kong, J., 2016. Magnetic Two-dimensional Molecularly

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Imprinted Materials for Recognition and Separation of Proteins. Phy. Chem., Chem. Phy., 18: 718-725. Crossgrove, J., Zheng ,W., 2004. NMR in Biomedicine, Manganese toxicity upon overexposure. NMR in Biomed., 17: 544-553. Contreras-Bustos, R., Manríquez-Reza, E., Jiménez-Becerril, J., Jiménez-Reyes, M., 2017. Synthesis of MnO2 on activated carbon and its potential application in the adsorption of As(V) and Pb(II) in aqueous solutions. Acta Chim. Slov. 64: 438-448.

17

ACCEPTED MANUSCRIPT Emadi M., Shams, E., Amini, M. K., 2012. Removal of zinc from aqueous solutions by magnetite silica core-shell nanoparticles. J. Chem. 2013:1-10 Emmanuel, K.A., Rao, A.V., 2008. Adsorption of Mn (II) from aqueous solutions using pithacelobium dulce carbon, Rasayan J. Chem. 1: 840-852. Foo, K.Y., Hameed, B.H., 2010. Insights into the modeling of adsorption isotherm systems.

PT

Chem. Eng. J., 156: 2-10. Fu F.,Wang Q. 2011. Removal of heavy metal ions from wastewaters: a review. J. Environ.

RI

Manage., 92: 407-418.

SC

Idrees, M., Batool, S., Hussain, Q., Ullah, H., Al-Wabel, M. I., Ahmad, M., Kong, J., 2016. High-efficiency remediation of cadmium (Cd2+) from aqueous solution using poultry

NU

manure–and farmyard manure–derived biochars. Sep. Sci. Technol. 51, 2307-2317. Idrees, M., Batool, S., Kalsoom, T., Yasmeen, S., Kalsoom, A., Raina, S., Zhuang, Q., Kong,

MA

J., 2018. Animal manure-derived biochars produced via fast pyrolysis for the removal of divalent copper from aqueous media. J. Environ. Manag., 213:109-118.

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Idrees, M., Batool, S., Kalsoom, T., Raina, S., Sharif, H. M. A., Yasmeen, S., 2018.

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Biosynthesis of silver nanoparticles using Sida acuta extract for antimicrobial actions and corrosion inhibition potential. Environ. Technol. 1-8. Kong, J. Schmalz, T., Motz, G., Müller, A. H. E., 2011. Novel hyperbranched ferrocene-

CE

containing poly(boro)carbosilanes synthesized via a convenient “A2+ B3” approach.

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Macromolecules 44: 1280-1291. Kurniawan, T.A., Chan, G.Y., Lo, W.H., Babel, S., 2006. Physico–chemical treatment techniques for wastewater laden with heavy metals. Chem. Eng. J., 118: 83-98. Lehmann, J., Joseph, S., 2009. Biochar for environmental management: an introduction, in: Biochar for Environmental Management Science and Technology. Earthscans., UK.112. Li, J., Hu, J., Sheng, G., Zhao, G., Huang, Q., 2009. Effect of pH, ionic strength, foreign ions and temperature on the adsorption of Cu(II) from aqueous solution to GMZ bentonite. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 349: 195-201. 18

ACCEPTED MANUSCRIPT Lim, J.E., Ahmad, M., Usman, v,S.S., Lee, S.S.W. Jeon, T., Oh, S. E., Yang, J.E., Ok, Y.S., 2013. Effects of natural and calcined poultry waste on Cd, Pb and As mobility in contaminated soil. Environ. Earth Sci., 69: 11-20. Limousin, G., Gaudet, J.P., Charlet, L., Szenknect, S., Barthes, V., Krimissa, M., 2007. Sorption isotherms: a review on physical bases, modeling and measurement. Appl. Geochem., 22: 249-275.

PT

Meng, L.L., Zhang, X. F., Tang, Y. S., Su, K.H., Kong, J., 2015. Hierarchically porous silicon–carbon–nitrogen hybrid materials towards highly efficient and selective

RI

adsorption of organic dyes Scientific Report 5: 7910.

SC

Naiya, T.K., Chowdhury, P., Bhattacharya, A.K., Das, S.K., 2009. Saw dust and neem bark as low-cost natural biosorbent for adsorptive removal of Zn (II) and Cd (II) ions from

NU

aqueous solutions, Chem. Eng. J., 148: 68-79.

Purakayastha, T.J., Kumari, S., Pathak, H., 2015. Characterisation, stability, and microbial

MA

effects of four biochars produced from crop residues. Geoderma 239: 293. Rachel, N.Y., Nsami, N.J., Daouda, K., Victoire, A.A., Benadette, T.M., Mbadcam, K.J.,

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2015. Adsorption of manganese (II) ions from aqueous solutions onto Granular

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Activated Carbon (GAC) and Modified Activated Carbon (MAC). Intern. J. Innovative Sci., Eng. & Technol., 2: 606-614. Saltali, K., Sari, A., Aydin, M., 2007. Removal of ammonium ion from aqueous solution by

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258-263.

CE

natural Turkish (Yıldızeli) zeolite for environmental quality. J. Hazard. Mater., 141:

Shafiq, M., Alazba, A.A., Amin, M.T., 2018. Removal of heavy metals from wastewater using date palm as a biosorbent: A comparative review. Sains Malaysiana 47: 35-49. Tavlieva, M. P., Geneiva, S. D., Georgieva, V. G., Vlaev, L. T., 2015. Thermodynamics and kinetics of the removal of manganese (II) ions from aqueous solutions by white rice husk ash. J. Molecular Liquids 211: 938-947. Üçer, A., Uyanik, A., Aygün, Ş.F,., 2006. Adsorption of Cu (II), Cd (II), Zn (II), Mn (II) and Fe (III) ions by tannic acid immobilised activated carbon, Sep. Purif. Technol. 47: 113-118. 19

ACCEPTED MANUSCRIPT Zhao, W. F., Tang, Y. S., Xi, J., & Kong, J., 2015. Functionalized graphene sheets with poly (ionic liquid) s and high adsorption capacity of anionic dyes. Appl. Surf. Sci., 326: 276-284. Zhou, H., Chen, Q., Li, G., Luo, S., Song, T.B., Duan, H.S., Yang, Y., 2014. Interface

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engineering of highly efficient perovskite solar cells. Sci., 345: 542-546.

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Figures and Tables Captions Fig. 1 Fourier transform infrared (FTIR) spectra of (a) farmyard manure-derived biochar

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(FBC), (b) poultry manure-derived biochar (PBC), (c) Mn-loaded FBC and (d) Mn-loaded PBC.

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Fig. 2 Scanning electron micrographs (SEM) of (a) farmyard manure-derived biochar (FBC)

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and (b) poultry manure-derived biochar (PBC)

Fig. 3 X-ray photon spectra (XPS) of (a) farmyard manure-derived biochar (FBC) and poultry manure-derived biochar (PBC), (b) Mn-loaded FBC and Mn-loaded PBC and (c)

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Thermogravimetric analysis (TGA) of farmyard manure-derived biochar (FBC) and poultry manure-derived biochar (PBC).

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Fig. 4 Effects of (a) pH, (b) temperature and (c & d) metal initial concentration on Mn removal the efficiency of manure-derived biochars.

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Fig. 5 Linear regression fittings of the Mn equilibrium sorption data to (a&b) the Freundlich

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and (c&d) Langmuir models at three different temperatures of 298, 308 and 318 K.

Fig. 6 (a) Effect of contact time on sorption of Mn onto manure-derived biochars (adsorbent dose 10 g L-1, temperature 308 and 318 K), (b) Van’t Hoff plot between LnK and 1/T for Mn

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sorption onto manure-derived biochars.

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Table 1 Constant parameters and correlation coefficients of isothermal models for Mn sorption onto manure-derived biochars.

Table 2 Comparison of adsorption capacity of Mn with other adsorbents.

Table 3 Thermodynamic parameters of Mn sorption onto manure-derived biochars.

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ACCEPTED MANUSCRIPT Fig. 1 Fourier transform infrared (FTIR) spectra of (a) farmyard manure derived biochar (FBC), (b) poultry manure derived biochar (PBC), (c) Mn-loaded FBC and (d) Mn-loaded PBC. Fig. 2 Scanning electron micrographs (SEM) of (a) farmyard manure-derived biochar (FBC) and

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(b) poultry manure-derived biochar (PBC).

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Fig. 3 X-ray photon spectra (XPS) of (a) farmyard manure-derived biochar (FBC) and

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poultry manure-derived biochar (PBC), (b) Mn-loaded FBC and Mn-loaded PBC and (c) Thermogravimetric analysis (TGA) of farmyard manure-derived biochar (FBC) and poultry

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manure-derived biochar (PBC).

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Fig. 4 Effects of (a) pH, (b) temperature and (c & d) metal initial concentration on Mn removal efficiency of manure-derived biochars.

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Fig. 5 Linear regression fittings of the Mn equilibrium sorption data to the Freundlich (a&b),

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Langmuir (c&d) models at three different temperatures of 298, 308 and 318 K. Fig. 6 (a) Effect of contact time on sorption of Mn onto manure-derived biochars (adsorbent

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dose 10 g L-1, temperature 308 and 318 K), (b) Van’t Hoff plot between LnK and 1/T

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for Mn sorption onto manure-derived biochars.

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ACCEPTED MANUSCRIPT Table 1 Constant parameters and correlation coefficients of isothermal models for Mn sorption onto manure-derived biochars Adsorbents

Temperature (K)

Freundlich KF

Langmuir N

R2

[(mg -1)

Temkin

KL

Qm

(L mg-1)

(mg g-1)

R2

B

A

(J mol-1)

(L g-1)

R2

(L g-1)n] 1.306

0.984

0.092

6.652

0.998

2942

9.634

0.922

308

0.258

1.501

0.975

0.292

1.341

0.975

4817

2.950

0.773

318

0.131

1.278

0.956

0.118

1.342

0.980

5068

0.675

0.686

298

1.103

1.863

0.809

1.056

2.403

0.479

3603

285.6

0.949

308

0.322

1.451

0.984

0.338

1.527

0.972

4166

4.520

0.805

318

0.167

1.390

0.982

0.057

2.842

0.979

5671

1.199

0.867

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0.520

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PBC

298

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FBC

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ACCEPTED MANUSCRIPT Table 2 Comparison of adsorption capacity of Mn with other adsorbents qm (mg g-1)

References

Pithacelobium dulce carbon

0.415

Emmanuel and Rao., 2008

Granular activated carbon

6.94

Rachel et al., 2015

Steam activated carbon

9.52

Akl et al., 2013

Activated carbon modified by nitric acid

10.00

Akl et al., 2013

Activated carbon modified by persulfate

6.66

Akl et al., 2013

Activated carbon modified by iron oxide

14.49

Rachel et al., 2015

Activated carbon immobilized by tannic acid

1.73

Üçer et al., 2006

Farmyard manure derived biochar

6.652

Poultry manure derived biochar

2.842

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Adsorbents

This study

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This study

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ΔGo

ΔHo

ΔSo

(kJ mol-1)

(kJ mol-1)

(J mol-1 K-1)

298

-34.88

-68.92

308

-33.03

318

-32.61

298

-37.44

308

-34.02

318

-32.90

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(K)

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-105.6

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PBC

Thermodynamic parameters

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FBC

Temperature

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Adsorbents

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Table 3 Thermodynamic parameters of Mn sorption onto manure-derived biochars

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-115.0

-229.8

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Highlights Biochar, a by-product of pyrolysis, was prepared as a low cost adsorbent precursor.



Effect of derived biochars on Manganese removal efficiency was investigated.



FBC and PBC characteristics were analyzed.

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Langmuir and Freundlich models were used for equilibrium modeling.

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Adsorption data agreed well with a pseudo-second-order kinetic model.

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Graphics Abstract

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6