Unravelled keratin-derived biopolymers as novel biosorbents for the simultaneous removal of multiple trace metals from industrial wastewater

Abstract

Biopolymers derived from modified poultry feathers (KB) were developed to target a broad range of potentially toxic trace elements for their removal from synthetic wastewater and industrial process affected water. The chemical modifications increased surface functionality of KBs for enhanced metal adsorption. Unmodified KB (SM-03) added to synthetic wastewater spiked with nine transition and redox sensitive elements (30-50 μg L^-1 each) removed >82% of Pb, Ni, Co and Zn, whereas modified KBs (SM-01 and SM-06) removed 68-100% of Se^IV, V^V and Cr^VI. Similar results were observed when spiked process water was used. Experimental observation suggested chemical reduction of redox sensitive elements on the modified KB surfaces to their non-toxic/non-mobile redox states. Biopolymer SM-06 showed a maximum adsorption capacity of 17 mg g^-1 for V^V and 15 mg g^-1 for Cr^VI at ~20 °C. Due to the abundance of raw material and simplicity of the modifications presented here, modified KBs may serve as a useful option for large-scale water treatment.

Keywords: Biopolymer; Biosorbent; Keratin; Trace metals; Wastewater.