title: Microbial fuel cells for sulfide removal.
abstract: Thus far, microbial fuel cells (MFCs) have been used to convert carbon-based substrates to electricity. However, sulfur compounds are ubiquitously present in organic waste and wastewater. In this study, a MFC with a hexacyanoferrate cathodic electrolyte was used to convert dissolved sulfide to elemental sulfur. Two types of MFCs were used, a square type closed to the air and a tubular type in which the cathode compartment was open to the air. The square-type MFCs demonstrated a potential-dependent conversion of sulfide to sulfur. In the tubular system, up to 514 mg sulfide L(-1) net anodic compartment (NAC) day(-1) (241 mg L(-1) day(-1) total anodic compartment, TAC) was removed. The sulfide oxidation in the anodic compartment resulted in electricity generation with power outputs up to 101 mW L(-1) NAC (47 W m(-3) TAC). Microbial fuel cells were coupled to an anaerobic upflow anaerobic sludge blanket reactor, providing total removals of up to 98% and 46% of the sulfide and acetate, respectively. The MFCs were capable of simultaneously removing sulfate via sulfide. This demonstrates that digester effluents can be polished by a MFC for both residual carbon and sulfur compounds. The recovery of electrons from sulfides implies a recovery of energy otherwise lost in the methane digester.
authors.affiliation: Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium. Korneel.Rabaey@ugent.be
authors.forename: Korneel
authors.initials: K
authors.lastname: Rabaey
authors.forename: Kirsten
authors.initials: K
authors.lastname: Van de Sompel
authors.forename: Lois
authors.initials: L
authors.lastname: Maignien
authors.forename: Nico
authors.initials: N
authors.lastname: Boon
authors.forename: Peter
authors.initials: P
authors.lastname: Aelterman
authors.forename: Peter
authors.initials: P
authors.lastname: Clauwaert
authors.forename: Liesje
authors.initials: L
authors.lastname: De Schamphelaire
authors.forename: Hai The
authors.initials: HT
authors.lastname: Pham
authors.forename: Jan
authors.initials: J
authors.lastname: Vermeulen
authors.forename: Marc
authors.initials: M
authors.lastname: Verhaege
authors.forename: Piet
authors.initials: P
authors.lastname: Lens
authors.forename: Willy
authors.initials: W
authors.lastname: Verstraete
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism*; D001674:Bioelectric Energy Sources; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D012722:Sewage; D013440:Sulfides / Q000302:isolation & purification*
chemical_list: D012722:Sewage; D013440:Sulfides