Removal of bisphenol A by Fe-impregnated activated carbons.

A commercial wood-based activated carbon and the oxidized counterpart were impregnated with iron. The two Fe-impregnated carbons were prepared and characterized for their iron content, textural characteristics, surface chemistry, and their performance for bisphenol A adsorption. Batch adsorption experiments were conducted to study the effect of pH, ionic strength, kinetics, and thermodynamic equilibrium. Equilibrium adsorption data were described by both Langmuir and Freundlich isotherms. The iron impregnated activated carbon and the oxidized impregnated activated carbon presented maximum adsorption capacities of 785.65 and 469.78 mg/g, respectively, while adsorption followed second-order rate kinetics for both impregnated carbons. According to the thermodynamic parameters (ΔΗο, ΔSo, ΔGo), the adsorption is a spontaneous, exothermic, and physical process. Fenton-driven experiments conducted at different molar ratios of [H2O2]/[BPA] showed efficient degradation of BPA in spent Fe-impregnated carbons up to 82-95%, with traces of hydroxylated products.