title: Unveiling characteristics of a bioelectrochemical system with polarity reversion for simultaneous azo dye treatment and bioelectricity generation.
abstract: A novel bioelectrochemical system (BES) operated with polarity reversion was explored for simultaneous anaerobic/aerobic treatment of azo dye and production of bioelectricity under extremely low buffer. The Congo red was first decolorized in anode, with completed color removal in 35 h. The resultant decolorization intermediates were then mineralized after the anode reversed to aerobic biocathode, evidenced by 55 % chemical oxygen demand (COD) removal in 200 h. The mineralization efficiency was further increased to 70 % when the period of the half-cycle was prolonged to 375 h. Meanwhile, the BES produced a continuous stable positive/negative alternate voltage output under 5 mM phosphate buffer because of the self-neutralization of the accumulated protons and hydroxyl ions in electrolyte. The electrode performance was significantly improved, which was indicated by alleviated electrode polarization, due to in situ use of accumulated protons and hydroxyl ions and enhanced electron transfer in the presence of Congo red and its degradation intermediates, which resulted in 1.05-fold increases in maximum power density (67.5 vs. 32.9 mW/m(2)). An analysis of the microbial diversity in the biofilm revealed that the biofilm was dominated by facultative bacteria with functional roles in contaminant degradation and electricity generation.
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China, sunjian472@163.com.
authors.forename: Jian
authors.initials: J
authors.lastname: Sun
authors.forename: Yaping
authors.initials: Y
authors.lastname: Zhang
authors.forename: Guoguang
authors.initials: G
authors.lastname: Liu
authors.forename: Xunan
authors.initials: X
authors.lastname: Ning
authors.forename: Yujie
authors.initials: Y
authors.lastname: Wang
authors.forename: Jingyong
authors.initials: J
authors.lastname: Liu
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D001391:Azo Compounds / Q000378:metabolism*; D001419:Bacteria / Q000145:classification / Q000254:growth & development*; D044822:Biodiversity; D001674:Bioelectric Energy Sources; D018441:Biofilms / Q000254:growth & development; D057919:Biological Oxygen Demand Analysis; D003224:Congo Red / Q000378:metabolism; D004560:Electricity; D004566:Electrodes / Q000382:microbiology; D013997:Time Factors
chemical_list: D001391:Azo Compounds; D003224:Congo Red