Microbe-assisted sulfide oxidation in the anode of a microbial fuel cell.
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 So, Sx(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 So/Sx(2-) and further to S4O6(2-)/S2O3(2-) occurred spontaneously as electrochemical reactions, and electricity was generated. The formation of So/Sx(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.
Sun
Min
M
Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China.
Mu
Zhe-Xuan
ZX
Chen
You-Peng
YP
Sheng
Guo-Ping
GP
Liu
Xian-Wei
XW
Chen
Yong-Zhen
YZ
Zhao
Yue
Y
Wang
Hua-Lin
HL
Yu
Han-Qing
HQ
Wei
Li
L
Ma
Fang
F
D001674:Bioelectric Energy Sources / Q000382:microbiology*; D019149:Bioreactors / Q000382:microbiology; D004560:Electricity; D004566:Electrodes / Q000382:microbiology; D010084:Oxidation-Reduction; D012996:Solutions; D013057:Spectrum Analysis; D013440:Sulfides / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism; D016999:Sulfur-Reducing Bacteria / Q000378:metabolism*
D012996:Solutions; D013440:Sulfides; D013455:Sulfur