Comparison of different semipermeable membranes for power generation and water flux in osmotic microbial fuel cells

BACKGROUNDCombining a forward osmosis membrane with a microbial fuel cell (OsMFC) has shown improved electricity generation compared with conventional MFCs due to the enhanced proton transport based on the osmotically driven water flux across the semi-permeable membrane. However, the impact of membrane materials on the performance of OsMFCs has yet to be systematically investigated. This study examines the characteristics of different semi-permeable membranes (cellulose triacetate (CTA) nonwoven (NW), CTA embedded support (ES), and polyamide (PA)), and then compares the performances of OsMFCs having these membranes. RESULTSThe OsMFC having CTA ES exhibited the highest electricity generation (current: 1.62 mA; maximum power density: 0.64 W m(-2)) although CTA ES showed lower proton transport ability and higher mass transfer resistance compared with PA. These results were due to the fact that CTA ES is less permeable to oxygen, such that anaerobic anode bacteria in the OsMFC having CTA ES were less inhibited by oxygen diffusion through the membrane than PA. Similarly, the highest water flux (0.83 L m(-2) h(-1))) was observed for CTA ES, even though CTA ES had a lower water flux than PA in the FO test. CONCLUSIONThis study confirms that CTA ES a more suitable membrane for OsMFCs than either PA or CTA NW. (c) 2015 Society of Chemical Industry