A Review on the Removal of Heavy Metals from Wastewater by Microbial Fuel Cells

Heavy metals are extremely harmful environmental pollutants due to their toxicity, non-biodegradability and environmental accumulation that can affect people and the environment. Microbial fuel cells are a type of bioelectrochemical approach in which bacterial species remove organic pollutants and metal ions from synthetic and industrial wastewater and simultaneously generate electricity. Currently, the real applications of these devices in the world are limited due to the low level of production density. According to the investigations carried out in this article in recent years, microbial fuel cells have been used as one of the ways to remove heavy metals from industrial effluents, and 10 to 100% removal rates were achieved for metals such as gold, chromium, copper, lead, cadmium, mercury, zinc, arsenic and nickel. Also, the parameters affecting the amount of removal were evaluated in these studies, and the optimal conditions are in most cases in the range of neutral pH and in some cases in pH=2, at a temperature of 22 to 35 0C and an external resistance of 200 to 1000 ohms.