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.