Characterization of Polyester Cloth as an Alternative Separator to Nafion Membrane in Microbial Fuel Cells for Bioelectricity Generation Using Swine Wastewater

Polyester cloth (PC) was selected as a prospective inexpensive substitute separator material for microbial fuel cells (MFCs). PC was compared with a traditional Nafion proton exchange membrane (PEM) as an MFC separator by analyzing its physical and electrochemical properties. A single layer of PC showed higher mass transfer (e.g., for O-2/H+/ions) than the Nafion PEM; in the case of oxygen mass transfer coefficient (k(o)), a rate of 50.0 x 10(-5) cm.s(-1) was observed compared with a rate of 20.8 x 10(-5) cm/s in the Nafion PEM. Increased numbers of PC layers were found to reduce the oxygen mass transfer coefficient. In addition, the diffusion coefficient of oxygen (D-O) for PC (2.0-3.3 x 10(-6) cm(2)/s) was lower than that of the Nafion PEM (3.8 x 10(-6) cm(2)/s). The PC was found to have a low ohmic resistance (0.29-0.38 Omega) in the MFC, which was similar to that of Nafion PEM (0.31 Omega); this resulted in comparable maximum power density and maximum current density in MFCs with PC and those with Nafion PEMs. Moreover, a higher average current generation was observed in MFCs with PC (104.3 +/- 15.3 A/m(3)) compared with MFCs with Nafion PEM (100.4 +/- 17.7 A/m(3)), as well as showing insignificant degradation of the PC surface, during 177 days of use in swine wastewater. These results suggest that PC separators could serve as a low-cost alternative to Nafion PEMs for construction of cost-effective MFCs.