Enhanced performance of sulfate reducing bacteria based biocathode using stainless steel mesh on activated carbon fabric electrode

Abstract

An anoxic biocathode was developed using sulfate-reducing bacteria (SRB) consortium on activated carbon fabric (ACF) and the effect of stainless steel (SS) mesh as additional current collector was investigated. Improved performance of biocathode was observed with SS mesh leading to nearly five folds increase in power density (from 4.79 to 23.11 mW/m(2)) and threefolds increase in current density (from 75 to 250 mA/m(2)). Enhanced redox currents and lower Tafel slopes observed from cyclic voltammograms of ACF with SS mesh indicated the positive role of uniform electron collecting points. Differential pulse voltammetry technique was employed as an additional tool to assess the redox carriers involved in bioelectrochemical reactions. SRB biocathode was also tested for reduction of volatile fatty acids (VFA) present in the fermentation effluent stream and the results indicated the possibility of integration of this system with anaerobic fermentation for efficient product recovery.

Keywords: ACF; Activated carbon fabric (ACF); CD; CDP; CEM; COD; CV; DPV; FS; Fermentation effluents; GC; MFC; Microbial fuel cell (MFC); OCV; ORP; PD; R(p); RS; SRB; SS; Stainless steel mesh; TEA; VFA; activated carbon fabric; cation exchange membrane; cell design point; chemical oxidation demand; current density; cyclic voltammetry; differential pulse voltammetry; forward sweep; gas chromatograph; microbial fuel cell; open circuit voltage; oxidation reduction potential; polarization resistance; power density; reverse sweep; stainless steel; sulfate reducing bacteria; terminal electron acceptor; volatile fatty acids.