Inhibition Strategies of Reverse Solute Flux in Osmotic Microbial Fuel Cells: Take Forward Osmosis as Reference

The osmotic microbial fuel cell (OsMFC) is formed bycombiningforward osmosis (FO) and microbial fuel cells (MFC). Its excellentperformance undoubtedly provided a new research direction for theapplication of FO and MFCs. However, the reverse solute flux (RSF)in FO also follows. RSF will cause a series of negative effects suchas loss of draw solutions, decrease of water flux, and electricitygeneration. Therefore, inhibition of RSF is very necessary for thepractical application of OsMFCs. Currently, there are much researchand related reviews on RSF inhibition in FO but few studies on OsMFCs.To provide some new ideas for the inhibition of RSF in OsMFCs, wefocused on three aspects: operating conditions, draw solutions, andFO membranes. Existing studies have demonstrated that some strategiesare effective in OsMFC, including inhibitory effect of current generation,conventional inorganic draw solutions, membrane materials and orientation,and modified membranes. But there are many more strategies available.Using FO as a reference, strategies such as pressure-assisted osmosisand temperature control may be feasible and need to be investigatedfurther. In the future, the inhibition or utilization of RSF can furtherimprove the reactor performance and promote the early practical applicationof OsMFCs.