Water Formation At The Cathode And Sodium Recovery Using Microbial Fuel Cells (MFCs)

Microbial Fuel Cells (MFCs) utilise biodegradable carbon compounds in organic waste to generate electric current. The aim of this work was to enhance MFC performance by using low cost and catalyst (platinum)-free cathode materials. The results showed that the range of Pt-free cathodes including activated carbon, plain carbon fibre veil with and without microporous layer (MPL) in two-chamber MFCs generated power with simultaneous catholyte generation in the cathode chamber. This is the first time to report a clear catholyte formation on the cathode half cell, which was directly related to MFC power per- formance. The importance of this phenomenon may be attributed to the oxygen reduction reaction, water diffusion and electroosmotic drag. The synthesised catholyte in situ on the open-to-air cathode appeared to be sodium salts (9% w/v concentration), which was recovered from the anolyte feedstock containing sludge and sodium acetate. An overlooked benefit of catholyte formation and accumulation contributes greatly to the overall wastewater treatment, water recovery, bioremediation of salts and carbon capture.