Enhanced Cr(VI) removal and power generation in Tannery Wastewater Using ORR-Optimized Cathodes in single-chamber microbial fuel cells

Abstract

The environment and human health are seriously threatened by hazardous heavy metals, including hexavalent chromium [Cr(VI)]. Single-chamber microbial fuel cell (MFC), which represents a simple and cost-effective configuration, is an emerging technology to convert low-value waste streams into renewable energy that has been extensively used in the bioremediation of Cr(VI)containing wastewater. This study aims to develop a simple strategy for enhancing Cr(VI) bioremediation and electricity generation in MFCs treating real tannery wastewater. This strategy involves the optimization of anodic biofilm that is capable of degrading organic substrates even in the presence of high Cr(VI) levels and the development of cost-effective, highly efficient oxygen reduction reaction (ORR) cathodic electrocatalysts to replace precious ORR catalysts (e.g., Pt/C).We observed that MFCs equipped with Pt/C and Ag 2 O-MnO 2 /rGO-NiPc cathodes exhibited 2 relatively higher power output (i.e., 24.76 and 21.14 mW/m 3 , respectively) compared to 19.94 mW/m 3 for PdO-MnO 2 /rGO-MFC and 13.21 mW/m 3 for the control MFC. Our research offers a promising strategy to enhance the overall efficiency of MFCs for treating tannery wastewater contaminated with Cr(VI).