PPy/AQS (9, 10-anthraquinone-2-sulfonic acid) and PPy/ARS (Alizarin Red's) modified stainless steel mesh as cathode membrane in an integrated MBR/MFC system

• PPy/AQS, PPy/ARS and PPy successfully modified SSM were tested in MBR/MFC for the first time.
• The modified SSMs function as conductive membranes and catalytic cathodes.
• The modification of SSM improved MB degradation and antifouling properties.
• The modification of SSM improved electricity generation by 20–30 times.
• The MBR/MFC with modified SSM has higher effluent quality and treatment efficiency.

To increase effluent quality and membrane flux, membrane bioreactor was integrated with microbial fuel cell (MBR/MFC), in which functional cathode membranes could enable fouling reduction and even electro-catalytic pollutant degradation using the bio-generated electricity. Modifying stainless steel mesh (SSM) with only polypyrrole (PPy) or cheap ARS (Alizarin Red's) or expensive AQS (9,10-anthraquinone-2-sulfonic acid) doped PPy film, helped obtain high ORR (oxygen reduction reaction) activity and higher power output in the integrated MBR/MFC system. The ARS and PPy modified cathode membranes, could not only increase the degradation of (MB) methylene blue (> 90%, 1 h), but also enable higher antifouling property in filtrations. Most importantly, replacing the blank SSM, the use of PPy/AQS, PPy/ARS and PPy modified SSM, increased power density 31.37, 27.06 and 23.7 times respectively in the integrated MBR/MFC system. The new system has great application potential and economic feasibility in effective removal of COD and NH4+-N nutrients, has better effluent qualities and has higher energy recovery.