Interface resistances of anion exchange membranes in microbial fuel cells with low ionic strength.
The interface resistances between an anion exchange membrane (AEM) and the solution electrolyte were measured for low buffer (or ionic strength) of electrolytes typical of microbial fuel cells (MFCs). Three AEMs (AFN, AM-1, and ACS) having different properties were tested in a flat-plate MFC to which 5-mM acetate was fed to the anode and an air-saturated phosphate buffer (PB) solution was fed to the cathode. Current density achieved in the MFCs was correlated inversely with independently measured membrane-only resistances. However, the total interfacial resistances measured by current-voltage plots were approximately two orders higher than those of the membrane-only resistances, although membranes had the same order as with the membrane-only resistance. EIS spectra showed that the resistances from electric-double layer and diffusion boundary layer were the main resistances not the membrane's resistance. The electric-double layer and diffusion boundary layer resistances of the AEMs were much larger in the 10 mM PB electrolyte, compared to 100 mM PB. EIS study also showed that the resistance of diffusion boundary layer decreased due to mechanical stirring. Therefore, the interface resistance that originates from the interaction between the membrane and the catholyte solution should be considered when designing and operating MFC processes with an AEM. The AEMs allowed transport of uncharged O(2) and acetate, but the current losses for both were low during normal MFC operation.
School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Buk-gu, Gwangju, Republic of Korea.
Eunkyoung
E
Ji
Hyunsoo
H
Moon
Jingmei
J
Piao
Phuc Thi
PT
Ha
Junyeong
J
An
Daehee
D
Kim
Jung-Je
JJ
Woo
Yonghee
Y
Lee
Seung-Hyeon
SH
Moon
Bruce E
BE
Rittmann
In Seop
IS
Chang
D000085:Acetates / Q000737:chemistry; D000838:Anions / Q000737:chemistry*; D001674:Bioelectric Energy Sources; D058266:Dielectric Spectroscopy; D007474:Ion Exchange; D008567:Membranes, Artificial; D009994:Osmolar Concentration; D010100:Oxygen / Q000737:chemistry
D000085:Acetates; D000838:Anions; D008567:Membranes, Artificial; D010100:Oxygen