Enhanced benzene bioremediation and power generation by double chamber benthic microbial fuel cells fed with sugarcane waste as a substrate

Benzene in wastewater poses severe toxic effects on living organisms and the environment. For this study, the possibility of using benthic microbial fuel cells (BMFC) for bioremediation of benzene using sugar cane waste as a substrate, while simultaneously producing bioenergy was studied. A BMFC is a membrane-less microbial fuel cell. Benzene was oxidised into intermediate benzoic acid then completely converted to carbon dioxide. The maximum potential was calculated using a multimetre, while current density and power density through the polarization curve. UV–visible spectroscopy and cyclic voltammetry were used to determine bioremediation efficiency and capacitance respectively. Electrochemical impedance spectroscopy determined the overall internal resistance and microbiological analysis revealed the bacteria present. Voltage of 430 mV was generated between 40 and 80 days at an external resistance of 1 kΩ. Within 40 days, a maximum power density of 24.2 mW/m2 and current density of 95 mA/m2 was generated. Also, the bioremediation efficiency of benzene was 82.3%. The optimum oxidation and reduction curve at day 40 was 0.1 V (forward peak) and −0.4 V (reverse peak) with a capacitance of 0.00004 F/g. The fitting equivalent circuit analysis measured an overall internal resistance (161.51 Ω) with the help of Nyquist plot. The SEM images showed holes in an irregular manner distributed over the electrode's surface. These holes represent excellent behaviour for developing biofilm. The 16S rDNA pyro-sequencing results identified Pseudomonas sp. and Bacillus sp. This is the first report of sugar cane waste as a substrate in a BMFC to bioremediate benzene along with power generation. These results showed that the BMFC could be used for power generation and benzene bioremediation. [Display omitted]