Studying microbial fuel cells equipped with heterogeneous ion exchange membranes: Electrochemical performance and microbial community assessment of anodic and membrane-surface biofilms.

In this study, microbial fuel cells deploying heterogeneous ion exchange membranes were assessed. The behavior of the cells as a function of the membrane applied was evaluated in terms of maximal current density, electron recovery efficiency and energy production rate (up to 427.5 mA, 47.7 % and 660 J m-2h-1, respectively) at different substrate (acetate) feedings (2.15 - 8.6 mM). System performance was characterized in the light of oxygen and acetate crossovers. The effect of membranes (in relation to the oxygen mass transfer coefficient, kO) on the microbial diversity of anodic and membrane-surface biofilms was investigated. Based on the relative abundance of bacterial orders, the two populations could be distinguished and membranes with larger kO tended to promote more the air-tolerant microbes in the biofouling layer. This indicates that membrane kO has a direct effect on membrane foulant microbial composition, and thus, on the expected time-stability of the membrane.

Efficiency, operational stability and biofouling of novel sulfomethylated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene cation exchange membrane in microbial fuel cells.

In this work, a novel cation exchange membrane, PSEBS SU22 was deployed in microbial fuel cells (MFCs) to examine system efficacy in line with membrane characteristics and inoculum source. It turned out that compared to a reference membrane (Nafion), employing PSEBS SU22 resulted in higher current density and electricity generation kinetics, while the electron recoveries were similar (19-28%). These outcomes indicated more beneficial ion transfer features and lower mass transfer-related losses in the PSEBS SU22-MFCs, supported by membrane water uptake, ion exchange capacity, ionic conductivity and permselectivity. By re-activating the membranes after (bio)foulant removal, PSEBS SU22 regained nearly its initial conductivity, highlighting a salient functional stability. Although the particular inoculum showed a clear effect on the microbial composition of the membrane biofouling layers, the dominance of aerobic species was revealed in all cases. Considering all the findings, the PSEBS SU22 seems to be promising for application in MFCs.