Improved recovery of bioenergy and osmotic water in an osmotic microbial fuel cell using micro-diffuser assisted marine aerobic biofilm on cathode

The research work demonstrated the performance of an integrated MFC capable of recovering osmotic water and electricity using forward osmosis in a double-chambered baffled channel reactor. The potential of applying electrochemically active (EA) aerobic marine biofilms on the cathode electrode was explored by eliminating the costly Pt-catalyst, thus making the system more eco-friendly and sustainable. The bio-cathode osmotic microbial fuel cell (OsMFC) used in this study was operated by two different conditions of oxygen supplied into the marine EA biofilms (i.e., the conventional oxygen supply by perforated pipes, and the enhanced oxygen supply by micro-pore air diffuser). The system recovered a maximum electrical power, 28.90 W m⁻³ net cathodic compartments (NCC), while removing 63 ± 8% of COD from raw domestic wastewater. The rate of osmotic water recovery was 1.46 ± 0.04 L m⁻² h⁻¹. The amount of recovered osmotic water showed a great potential for integrating osmosis into the marine bio-cathode OsMFC. The dominating bacterial communities identified in the cathodic biofilms were mainly gamma-Proteobacteria and alpha-Proteobacteria.