Ameliorated performance of a microbial fuel cell operated with an alkali pre-treated clayware ceramic membrane

Clayware membrane amalgamated with 20% montmorillonite (M-20), acts as an excellent cost effective proton exchange membrane (PEM) for the application in field-scale microbial fuel cells (MFCs). In this investigation, M-20 membrane was pre-treated by acid (M-A), neutral water (M-N) and alkali (M-B), followed by the determination of the membrane properties to access their applicability in MFCs. With alkali treatment of M-20 membrane, maximum proton mass transfer coefficient of 6 x 10(-6) cm s(-1) was obtained, which was nearly five times higher than M-A (1.15 x 10(-6) cm s(-1)) and four times higher than the control membrane, M-N. Proton conductivity was also found to be maximum for M-B (17.9 x 10(-3) S cm(-1)), which was four times higher than both M-N (4.4 x 10(-3) S cm(-1)) and MA (4.6 x 10(-3) S cm(-1)). Oxygen mass transfer coefficient was found to be minimum for M-B (4.02 x 10(-5) cm s(-1)), which was considerably lesser than that observed for M-N (16.2 x 10(-5) cm s(-1)) and M-A (13.8 x 10(-5) cm s(-1)). Cation transport number of M-B (0.15 +/- 0.01) was found to be two folds lower than M-N, demonstrating M-B is more selective towards proton transport compared to other cations. The MFC-B with M-B as PEM performed superior as compared with other MFCs, demonstrating coulombic efficiency (CE) of 10.2%, chemical oxygen demand (COD) removal efficiency of 88% and power density of 83.5 mW m(-2). On the other hand, MFCs using M-A and M-N as PEM, demonstrated mediocre performance with CE of 6% and 7.6%, COD removal efficiency of 80% and 83% and power density of 40.4 +/- 6.2 mW m(-2) and 64.0 +/- 5.8 mW m(-2), respectively. Hence, alkali treatment of clayware ceramic membrane elucidated its appropriateness for proliferating the efficacy of MFCs and these are recommended for scaling up of MFCs. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.