Electrochemical Parameter Selection And Optimization Of Heavy Metal Detection Technology Based On Microbial Fuel Cell

In recent years, with the rapid development of industry, the water quality is more or less polluted, especially by heavy metal (Cu2+, Hg2+, Cd2+ and Pb2+etc.). Therefore, the on-line detection for water quality is very important. This study focused on the on-line detection of water quality by the MFC-based biosensor. Inhibition rates of different parameters (voltage output, current, anodic resistance, anodic capacitance, power density and electric quantity) in MFC-based biosensors was used to evaluate their suitability for monitoring the mercury and cadmium toxicity in the aquatic environment.Voltage output, current, anodic resistance, anodic capacitance, maximum power density and electric quantity were explored to represent the inhibition rates of mercury and cadmium on MFCs-based biosensors. The inhibition rate of mercury or cadmium on MFCs-based biosensors was unsuitable to represent with the parameters of anodic capacitance and electric quantity. When comparing the obtained results of inhibition rates on voltage, current, anodic resistance and the maximum power density, anodic resistance and the maximum power density are the better options to represent the inhibition effects of mercury or cadmium on MFC-biosensors because of the bigger inhibition rates at the same concentration of mercury or cadmium. When adding the mercury in MFC-based biosensors, the change of anodic resistance is the root cause of the other changes (voltage output, current, and maximum power density). The power is the product of voltage and current. Therefore, when choosing maximum power density rather than voltage output or current as the detecting index, the inhibition is magnified which was good for the on-line monitoring. Moreover, concerning the R-squares when fitting the inhibition rates at different mercury concentrations, anodic resistance and the maximum power density were still the better indexes for mercury or cadmium monitoring.MFC-based biosensors were effective for monitoring mercury ion and cadmium ion. The maximum power density are 1 the better indexes for mercury monitoring in aquatic environment, however, anodic capacitance and electric quantity were unsuitable. When concerning the value of inhibition rates, the inhibition rates of mercury was bigger than the inhibition rates of cadmium at the same concentration. Moreover, when concerning the R-squares fitting the inhibition rates at different mercury or cadmium concentrations, the (coefficient of determination) R2 of mercury at different concentration were better than R2 of cadmium at different concentration.