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.

Performance of a lab-scale bio-electrochemical assisted septic tank for the anaerobic treatment of black water

“…One of the possible reasons might be that part of the sulphides diffuses toward the anodic compartment. This is in agreement with Rabaey et al [24] who found that the diffusion of sulfides could occur even through a membrane. In addition, the corrosion of the anode (presence of iron salts in the bulk solution) could have a double positive effect on the H 2 S removal.…”

Microbial ecology meets electrochemistry: electricity-driven and driving communities

“…In addition to organic heterocyclic and monocyclic compounds, sulfur species and hydrogen can be used as electron shuttles (Lovley, 2000;Straub and Schink, 2004;Niessen et al, 2005;Rabaey et al, 2006). To mimic the microbial shuttling, redox-active compounds such as neutral red can be added to the anode compartment of an MFC (Park and Zeikus, 2000).…”

“…For example, a glucose-fed microbial fuel cell (MFC) had an order of magnitude more acetate in the effluent when the external resistance was 100 vs 20 O, with resulting anodic potentials of about À250 and 0 mV vs standard hydrogen electrode (SHE), respectively (Stefano Freguia, available online). This type of control has extensively been used for MFC research (Bond and Lovley, 2003;Rabaey et al, 2006). The colonization rate and growth yield of the bacteria changed as a function of the applied potential (Finkelstein et al, 2006), thus providing a system to examine how small changes in potential impact bacterial communities.…”

Dairy Waste Management for Bioelectric Production and CO2 Sequestration by Using a Microbial Fuel Cell (MFC)

“…A microbial fuel cell is a biological system in which bacteria do not directly transfer their produced electrons to their electron acceptor, rather transported over an anode, conducting wire and a cathode. Thus bacterial energy is directly converted into electrical energy (Rabaey et al, 2006). Research on microbial fuel cells has received increased attention as a means to produce "green" electricity from natural substances, such as carbohydrates, agricultural wastes or dairy waste.…”