Power Production In Microbial Fuel Cells Research Articles

Evaluation of full-strength paper mill effluent for electricity generation in mediator-less microbial fuel cells

In the search for renewable, sustainable and affordable energy sources, microbial fuel cells (MFCs) offer the advantage of a biological oxidation of pollutants to the direct generation of electricity by microorganisms. We thus examined the biodegradability and suitability of unamended paper mill effluent for power production in MFCs. In addition, an investigation of the response from indigenous waste microbes upon introduction of an exogenous Enterobacter cloacae culture was performed. Unamended effluent alone reached a substrate degradation rate (SDR) of 0.112 kg COD/m 3 day and 29.4 ± 2.4% total chemical oxygen demand (tCOD) removal, the power density peaked at 24 ± 3 mW/m 2 and 47.7% glucose increase at the termination of the reactor cycle after 12 ± 3 days. The introduction of E. cloacae in separate setups lowered electricity generation, but benefited remediation, power density decreased to 13 ± 2 mW/m 2 whereas the SDR increased to 0.257 kg COD/m 3 day. Also, there was 44.1% glucose removal in the presence of E. cloacae . It was concluded that unamended paper mill effluent can fuel electricity generation in MFCs with its concomitant remediation. The addition of E. cloacae to live paper mill effluent may be antagonistic in terms of electricity generation. Key words: Microbial fuel cells, paper mill effluent, bioremediation, substrate degradation rate, wastewater, renewable energy, electricity.

Flame synthesis of carbon nanostructures on stainless steel anodes for use in microbial fuel cells

Microbial fuel cells (MFCs) offer a promising alternative energy technology, but suffer from low power densities which hinder their practical applicability. In order to improve anodic power density, we deposited carbon nanostructures (CNSs) on an otherwise plain stainless steel mesh (SS-M) anode. Using a flame synthesis method that did not require pretreatment of SS-M substrates, we were able to produce these novel CNS-enhanced SS-M (CNS-M) anodes quickly (in a matter of minutes) and inexpensively, without the added costs of chemical pretreatments. During fed batch experiments with biomass from anaerobic digesters in single-chamber MFCs, the median power densities (based on the projected anodic surface area) were 2.9 mW m −2 and 187 mW m −2 for MFCs with SS-M and CNS-M anodes, respectively. The addition of CNSs to a plain SS-M anode via flame deposition therefore resulted in a 60-fold increase in the median power production. The combination of CNSs and metallic current collectors holds considerable promise for power production in MFCs.

Feasibility study of simultaneous bioelectricity generation and dye decolorization using naturally occurring decolorizers

This first-attempt study tended to uncover microbial characteristics of simultaneous bioelectricity generation and dye decolorization in air-cathode single-chamber microbial fuel cells (MFCs) using indigenous dye decolorizers (e.g., Acinetobacter johnsonii NIUx72, Enterobacter cancerogenus BYm30, Klebsiella pneumoniae ZMd31). Batch experimental results showed that supplementation of azo dye C.I. reactive blue 160 (RBu 160) simultaneously stimulated dye decolorization and bioelectricity generation for ZMd31. However, such additions of RBu 160 repressed bacterial activity of A. johnsonii NIUx72, E. cancerogenus BYm30 for power production in MFC. Apparently, selecting appropriate electrochemically active microbes is inevitably top-priority for simultaneous bioelectricity generation and dye decolorization in MFCs.

Assessment upon azo dye decolorization and bioelectricity generation by Proteus hauseri

This study explored dye decolorization and bioelectricity generation of indigenous Proteus hauseri ZMd44 for dye-bearing wastewater treatment. Chemical structures of azo dyes apparently affected the performance of dye biodecolorization. Additions of diazo dye C.I. reactive blue 160 (RBu160) stimulated simultaneous dye decolorization and bioelectricity generation of ZMd44 in single chamber microbial fuel cells (MFCs). However, high-level additions of RBu160 repressed capabilities of power production in MFC due to competition of electrons used for reductive decolorization. Decolorized intermediates of RBu160-phenyl methadiamine and 5-sulfoanthranilic acid as electron shuttles might mediate electron transport for current generation in MFC.

Effect of Inoculum Types on Bacterial Adhesion and Power Production in Microbial Fuel Cells

Microbial fuel cell (MFC) is an emerging biotechnology to convert the organic substrates in wastewater to electricity by anaerobic electrogenic bacteria. The main challenge for MFC research is to elucidate the fundamental mechanisms of electron generation and transfer and to apply these mechanisms to improve the power production in the engineering operation. This study extensively investigated the effects of three inocula (Geobacter sulfurreducens, soil, and wastewater) on the power production and electrochemical characteristics (i.e., internal resistances, Coulombic Efficiency) of MFCs. The results showed that the extents of bacterial adhesion varied between mixed cultures (soil) and pure cultures (G. sulfurreducens). The voltage output increased 30% when bacterial adhesion was well-developed in the soil inocula. Meanwhile, the inoculum types clearly affected the internal resistance (R(in)) and power production of MFCs. Pure culture inoculum (G. sulfurreducens) had the lowest R(in) (165 Omega) and the highest Coulombic Efficiency (CE, 25.8%) and Energy Conversion Efficiency (ECE, 7.2%), while the mixed culture inocula (soil) with the high concentration of nonelectrogenic bacteria, exhibited the highest R(in) (620 Omega), lowest CE (9.2%) and lowest ECE (2.4%). Additionally, a second-order correlation was established between the anode potential (P(A)) and power output while an exponential correlation was established between the difference between anode and cathode potentials (DeltaP(C-A)) and power output.