Abstract

SHIKUKU, Victor O.  and  JEMUTAI-KIMOSOP, Selly. Efficient Removal of Sulfamethoxazole onto Sugarcane Bagasse-derived Biochar: Two and Three-parameter Isotherms, Kinetics and Thermodynamics. S.Afr.j.chem. (Online) [online]. 2020, vol.73, pp.111-119. ISSN 1996-840X.  http://dx.doi.org/10.17159/0379-4350/2020/v73a16.

In this work, bagasse, an agricultural waste was used for the development of environmentally benign biochar (CBG) and the thermal pyrolysis product applied for adsorption of sulfamethoxazole (SMX) from water using a batch technique. The pseudo-first-order model best described the adsorption kinetics. Equilibrium adsorption data were modelled using six two-parameter and five three-parameter isotherm equations and the best-fitting models obtained using five error functions. The Sips isotherm best predicted the equilibrium data with an estimated adsorption capacity of 128.8 mg g^-1. Error analysis showed that three-parameter isotherms best explained the experimental data. The thermodynamic functions, viz. enthalpy (AH = -24.72 kJ mol^-1), Gibbs free energy (AG = -15.67 kJ mol^-1), entropy (AS = 32.65 kJ mol^-1), showed that the reaction is spontaneous and exothermic. The mechanism of adsorption involved charge-assisted hydrogen bonding (-)CAHB. The amount of CBG required for the removal of 99 % of SMX in a given volume of effluent was predicted. The results attest that CBG is an effective low-cost adsorbent for SMX adsorption.

Keywords : Sulfamethoxazole; adsorption; bagasse; pyrolysis; biochar.

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