Electrochemical evaluation of lab-scale chamber benthic microbial fuel cell

Abstract

Benthic microbial fuel cell (BMFC) utilizes naturally available exoelectrogens and organic matter present in the sediment to produce electrical energy. The practical limitation of BMFC is maybe due to the mass transport losses. Therefore, practical implications were deduced from two different types of lab-scale BMFC i.e. chamber-BMFC (C-BMFC) with pumping to avoid the accumulation and to increase diffusion rate; and sediment-BMFC (S-BMFC). Further, to identify sources of impedance losses, effect of the sediment height over anode was investigated in sterile media (sediment and seawater). In C-BMFC, anodes of equal size (3 cm × 3 cm) were deployed inside the chamber with two different volumes as 50 mL (50:3C) and 180 mL (180:3C). In S-BMFC anodes of two different sizes as 3 cm × 3 cm (3S) and 6 cm × 6 cm (6S) were deployed inside sediment. In-situ electrochemical techniques were implemented in BMFC to estimate diffusion impedance. The diffusion coefficient was found to be increasing with the sediment height in sterile media. Maximum power density generated by 6S, 3S, 50:3C, and 180:3C was 181, 201, 335.51, and 421.02 mW m−2 respectively. Impedance data shows microbial consortia play a vital role in the mass transport phenomena electrochemical diffusion in BMFC.