Reduction of vanadium(V) in a microbial fuel cell: V(IV) Migration and Electron Transfer Mechanism

摘要

The effects of vanadium on the microbial fuel cell performance, migration and distribution of V(Ⅳ) aswell as electron transfer mechanism of single-chamber MFC were investigated by SEM, FourierTransform Infrared Spectroscopy (FTIR), Cyclic Voltammetry (CV) and Electrochemical ImpedanceSpectroscopy (EIS). With anolyte vanadium concentration of 100 mg/L, the shortest degradation cyclewas 130.67 h, while the degradation rate was 99.44%. V(Ⅴ) combined with hydroxyl and carboxylgroups to form V(Ⅳ) organic participates, part of which deposited on the anode surface, and the otherpart distributed in anolyte. V(Ⅴ) around cathode was reduced to V(Ⅳ) receiving electrons from theanode, meanwhile V(Ⅴ) in anolyte was reduced to V(Ⅳ) owing to the electrons transfer on membranebinding enzyme complex. V(Ⅴ) participated in cathode reactions instead of oxygen, accelerating thesynchronization and integrity of electrode reactions.