Integrated Tea Polyphenols and Polydopamine Bidirectional Modified Graphene as Anode for Improved Bioelectricity Generation and Cr(Vi) Reduction in Microbial Fuel Cells

Abstract

Microbial fuel cells (MFCs) have the dual advantage of mitigating Cr(VI) wastewater ecological threats while generating electricity. However, the low electron transfer efficiency and the limited enrichment of active electrogens are barriers to MFCs advancement. This study describes the synthesis of the TP-PDA-RGO@CC negative electrode using tea polyphenol as a reducing agent and polydopamine-doped graphene, significantly enhances the roughness and hydrophilicity of the anode. The charge transfer resistance was reduced by 94%, and the peak MFC power was 1375.80 mW·m-2. Under acidic conditions, the Cr(VI) reduction rate reached 92% within 24 h, with a 52% increase in coulombic efficiency. Biodiversity analysis shows that the TP-PDA-RGO@CC anode could enrich electrogens, thereby boosting the electron generation mechanism at the anode and enhancing the reduction efficiency of Cr(VI) in the cathode chamber. This work emphasizes high-performance anode materials for efficient pollutant removal, energy conversion, and biomass reuse.

Keywords: Microbial fuel cell, Anode modification, Reduced graphene oxide, Tea polyphenol extract, Hexavalent chromium reduction