Microbial fuel cells for bioelectricity generation through reduction of hexavalent chromium in wastewater: A review

The study proposes the use of microbial fuel cell (MFC) technology to reduce toxic Cr(VI) present in industrial wastewater to less toxic trivalent chromium [Cr(III)], while generating electricity through a bioelectrochemical oxidation-reduction process. Factors influencing the treatment process and electricity generation include the concentration of Cr(VI) in wastewater, substrate types used for anodes, types of microorganisms involved, types of cathode and anode, surface area of the cathode and anode, and pH and temperature of cathodic and anodic solutions. While other heavy metals in wastewater may be removed by MFC technology, Cr(VI) removal is more efficient in terms of electricity generation. Previous research indicated that the maximum electrical power generated by Cr(VI) removal through the use of MFCs is 1600 mW/m², which is expected to increase as the factors affecting this process are optimized. Based on current data, MFC-based electricity generation along with Cr(VI) removal is a potential future source of sustainable energy. However, research priorities need to focus on reducing the cost of MFC technology by using economical and effective materials and increasing electricity production.