Removal of Sulfide and Production of Methane from Carbon Dioxide in Microbial Fuel Cells–Microbial Electrolysis Cell (MFCs–MEC) Coupled System

Abstract

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.

On the Edge of Research and Technological Application: A Critical Review of Electromethanogenesis

“…Siegert et al reported higher methane yields in biocathodes when hydrogenotrophic methanogens where presented in the inoculum [73]. In agreement with other studies [44,45,55], these findings suggest that the presence of Archaea of the hydrogenotrophic genera Methanobacterium and Methanobrevibacter are crucial to produce methane in BESs and their presence in the inoculum favours electromethanogenesis processes. Obviously methanogens must be included in a wide range of inoculum, but also the presence of effective electron uptake species will ensure a free electron flow from the electrode to electromethanogens unable to attach on the electrode surface.…”

“…In addition, methanogens have been found the main microbial community for the reduction of CO 2 into CH 4 in BES (Figure 3: reactions 1 and 6) [8,11,13,19,42,43]. Among such community, hydrogenotrophic methanogens (i.e., Methanobacterium or Methanobrevibacter ) have been found to play a main role (Figure 3: reaction 6) [19,44], specifically in studies dealing with mixed culture biocathodes in BESs [45]. Therefore favorable conditions for the growth and the activity of hydrogenotrophic methanogens, such as better bioavailability of H 2 , might lead to an increase in methane production by these systems.…”

“…In this study, Co(II) was added and subsequently reduced in the biocathode, while sodium acetate was oxidized in the bioanode, thus mimicking cathodic bioremediation and anodic WWT. Furthermore, Jiang et al performed anodic sulfide removal and cathodic electromethanogenesis in a microbial fuel cells-microbial electrolysis cell coupled system [44]. These proofs of concept demonstrate that a low energetic cost methodology for bioremediation through BESs is possible when electromethanogenesis occurs in the biocathode.…”

Methanobacterium Dominates Biocathodic Archaeal Communities in Methanogenic Microbial Electrolysis Cells

“…6 All other reports on non-thermophilic MECs have identified Methanobacterium or Methanobrevibacter as the predominant archaea. 16,17 Other, less abundant methanogens identified in these MECs were Methanocorpusculum, Methanosarcina and Methanoculleus species. 17,18 The materials, [19][20][21] surface area, 22 and set cathode potentials 20 are known to affect abiotic rates of hydrogen gas production, and it is unclear to what extent these reactor materials or operational conditions contribute to the enrichment of hydrogenotrophic methanogens.…”

Electrifying microbes for the production of chemicals

“…In sulfide-driven MES, the electricity required for MES is generated by the abiotic oxidation of the toxic contaminant sulfide to sulfur and the subsequent biological oxidation of sulfur to sulfate (Gong et al, 2013). A similar process has also been developed to supply electrons for the electroproduction of methane from CO 2 (Jiang et al, 2014). Moreover, MES and electromethanogenesis have been conducted in parallel with the biorecovery of cobalt at the cathode further illustrating the versatility of this technology (Huang et al, 2014).…”