Concurrent removal of As(III) and As(V) using green low cost functionalized biosorbent – Saccharum officinarum bagasse

•Thiol functionalized sugarcane bagasse reported for the removal of arsenic.•High uptake capacity for both As(III) and As(V) compared to other biosorbents.•Mechanism of removal has been postulated.•Applied to decontaminate arsenic contaminated groundwater.

The present study focuses on the uptake of As(III) and As(V) ions from aqueous solution using low cost, green, chemically modified biosorbent Saccharum officinarum bagasse commonly referred as sugarcane bagasse (SCB). Functionalization of SCB was carried out with 2-mercaptoethanol by incipient wet impregnation method. Material was characterized by SEM, EDAX and FTIR spectra. FTIR spectra provided evidence to the presence of potential binding sites associated with thiol groups which are responsible for As(III) and As(V) removal. The optimum equilibrium contact time, dose rate, isotherm and pH used for adsorption of As(III) and As(V) were studied. The adsorption data showed good fit to both Langmuir and Freundlich isotherm models. The Langmuir monolayer capacities for As(III) and As(V) were estimated to be 28.57 and 34.48 mg/g of SCB-S, respectively. It is simple, fast and economical method to adsorb arsenic from aqueous solution. Thermodynamic studies revealed negative value for ΔG indicating the spontaneity of the reaction and positive values for enthalpy and entropy indicated the endothermic nature of the reaction. Recyclability studies demonstrated the applicability up to 5 cycles without much depreciation in sorption capacity. Finally, the green sorbent was applied to the removal of both trivalent and pentavalent arsenic species from arsenic contaminated ground waters.

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