Enhancing the stability of power generation of single-chamber microbial fuel cells using an anion exchange membrane

BACKGROUD: A decreased power density could be observed in a single-chamber microbial fuel cell (MFC) with a cation exchange membrane (CEM), as a result of pH-associated problem and a precipitated salt-associated problem, due to the transport of cations other than protons through the membrane to the cathode. To inhibit cation transport and enhance the stability of power generation, an anion exchange membranes (AEM) was applied in a single-chamber MFC. RESULTS: After 70 days' operation, the power density dropped 29% in the MFC with an AEM (AMFC), smaller than 48% in the MFC with a cation exchange membrane (CMFC). The reason for this difference lay in internal resistance development. Membrane resistance in the AMFC remained the same but that in the CMFC was increased by 67 Omega, and the cathode resistance increase in the AMFC was 54 Omega, while that in the CMFC was 123 Omega. The precipitated cations on the cathode catalyst surface in the CMFC, which accounted for the resistance increase, were up to 84 times larger than that in the AMFC. CONCLUSION: Because of its capacity for inhibiting cations,the AMFC possessed more stable membrane and cathode resistances; thus an enhanced power generation was obtained. (C) 2009 Society of Chemical Industry