Removal of sulfide and production of methane from carbon dioxide in microbial fuel cells-microbial electrolysis cell (MFCs-MEC) coupled system.

Removal of sulfide and production of methane from carbon dioxide in microbial electrolysis cells (MECs) at the applied voltage of 0.7 V was achieved using sulfide and organic compound as electron donors. The removal rate of sulfide was 72% and the Faraday efficiency of methane formation was 57% within 70 h of operation. Microbial fuel cell (MFCs) can be connected in series to supply power and drive the reaction in MECs. Removal of sulfide and production of methane from carbon dioxide in MFCs-MEC coupled system was achieved. The sulfide removal rates were 62.5, 60.4, and 57.7%, respectively, in the three anode compartments. Methane accumulated at a rate of 0.354 mL h(-1) L(-1) and the Faraday efficiency was 51%. Microbial characterization revealed that the biocathode of MEC was dominated by relatives of Methanobacterium palustre, Methanobrevibacter arboriphilus, and Methanocorpusculum parvum. This technology has a potential for wastewater treatments and biofuel production from carbon dioxide.