Reduction of hexavalent chromium using sulphonated polyether ether ketone as proton exchange membrane in microbial fuel cells

Abstract

Hexavalent chromium (Cr(VI)) is a major source of environmental pollutants from tannery effluents. Reduction of hexavalent chromium was performed in a 500 mL working volume dual chamber microbial fuel cell (MFC). Synthetic wastewater containing Cr(VI) was used as anolyte and substrate for mixed microbial consortia to release electrons. The ions produced were transferred to cathodic chamber via a Proton Exchange Membrane (PEM). In this study, sulphonated polyether ether ketone (SPEEK) was used as PEM and compared with Nafion 117 for Cr(VI) reduction. The microbial consortia that aided the treatment were isolated and identified to belong to Enterobacter, Acinetobacter, Stenotrophomonas and Pseudomonas species. The Cr(VI) reduction observed were 14.4% and 51% for MFCs with Nafion 117 and SPEEK as PEM, respectively. The wastewater analysis also showed improved percentage removal for SPEEK than for Nafion 117. The cost analysis shows that Nafion was 2 times higher than SPEEK to be used as PEM. This study highlights that SPEEK as PEM in MFC will be an efficient method for reduction of Cr(VI) from tannery effluents.