Microbe-Assisted Sulfide Oxidation in the Anode of a Microbial Fuel Cell

• Published in: Environmental science & technology Vol. 43; no. 9; pp. 3372 - 3377
• Main Authors: Sun, Min, Mu, Zhe-Xuan, Chen, You-Peng, Sheng, Guo-Ping, Liu, Xian-Wei, Chen, Yong-Zhen, Zhao, Yue, Wang, Hua-Lin, Yu, Han-Qing, Wei, Li, Ma, Fang
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.05.2009
• Subjects: Applied sciences; Bioelectric Energy Sources - microbiology; Bioreactors - microbiology; Catalysis; Chemical reactions; Chromium; Electricity; Electrocatalysis; Electrodes - microbiology; Energy and the Environment; Exact sciences and technology; Fuel cells; Oxidation; Oxidation-Reduction; Pollution; Solutions; Spectrum Analysis; Sulfide compounds; Sulfides - metabolism; Sulfur; Sulfur - metabolism; Sulfur-Reducing Bacteria - metabolism; Persistence; Pollutant behavior; Bacteria; Oxidation; Electrochemical reaction; Microbial community; Speciation
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es802809m

Sulfide oxidation is coupled with electricity generation in a sulfide-fed microbial fuel cell (MFC). This study demonstrated that both electrochemical reactions and microbial catalysis were involved in such a complex sulfide oxidation process in the anode of an MFC. The microbe-assisted sulfide oxidation generated a higher persistent current density than the sulfide oxidation via single electrochemical reactions only. Three valence states of S (−II), S (0), and S (+VI) were discovered from the sulfide oxidation, and S0, S x 2−, S4O6 2−, S2O3 2−, and SO4 2− were detected as the intermediates. Based on the sulfur speciation and microbial community analysis, the sulfide oxidation pathways in the MFC were proposed. The oxidation of sulfide to S0/S x 2− and further to S4O6 2−/S2O3 2− occurred spontaneously as electrochemical reactions, and electricity was generated. The formation of S0/S x 2− and S2O3 2− was accelerated by the bacteria in the MFC anode, and SO4 2− was generated because of a microbial catalysis. The microbe-assisted production of S2O3 2− and SO4 2− resulted in a persistent current from the MFC.