Enhanced vanadium (V) reduction and bioelectricity generation in microbial fuel cells with biocathode

RuiQiu, JiaxinLi, QingLv, SongWang, QianGu

School of Water Resources and Environment, China University of Geosciences Beijing, Key Laboratory of Groundwater Circulation and Evolution (China University of Geosciences Beijing), Ministry of Education, Beijing 100083, China.

Abstract

Microbial fuel cells (MFCs) represent a promising approach for remediation of toxic vanadium (V) contaminated environment. Herein, enhanced V(V) reduction and bioelectricity generation are realized in MFCs with biocathode. Synergistically electrochemical and microbial reductions result in the nearly complete removals of V(V) within 7 d operation with initial concentration of 200 mg L^-1. Maximum power density of 529 ± 12 mW m^-2 is obtained. Electrochemical tests reveal that biocathode promotes electron transfers and reduces charge transfer resistance. XPS analysis confirms that V(IV) is the main reduction product, which precipitates naturally under neutral conditions. High-throughput 16S rRNA gene sequencing analysis indicates that the newly appeared Dysgonomonas is responsible for V(V) reduction and Klebsiella contributes mainly to bioelectricity generation in MFCs with biocathode. This study further improves the performance of remediating V(V) contaminated environment based on MFC technology.