Agro-industrial waste: A low-cost option for the biosorptive remediation of selenium anions

Abstract

For remediation purposes, initially, the screening and selection of potent biosorbent, among three agro-industrial wastes (i.e., wheat bran, maize bran, and rice bran) was done. Wheat bran was found to show maximum uptake in the case of both Se(IV) and Se(VI) ions. Effect of various parameters (pH, temperature, initial metal ion concentration, and biomass dose) was extensively investigated on the uptake of these metal ions by potent biosorbent using batch mode. Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models were applied and all three isotherms fitted well to sorption data. The maximum sorption capacity of wheat bran was 89.28 μg/g for Se(VI) and 80.65 μg/g for Se(VI) at 20 °C and pH 2.0. Values of mean sorption energy indicated sorption to be chemisorption. Thermodynamic study revealed that sorption was feasible, spontaneous and exothermic. The sorption reaction was determined to be pseudo-second-order. Fourier transform infrared (FTIR) analysis of raw and metal-loaded biosorbent was done to determine changes on the surface of the sorbent after sorption. © 2010 American Chemical Society.