Study on the Performance of Two-Compartment Microbial Fuel Cells Under Different Heavy Metal Concentrations

In order to explore the influence of different heavy metal concentration conditions on the remediation of Pb and Cd in paddy soil by MFCs (microbial fuel cells) device, and compare the concentrations of Pb and Cd that are most suitable for its operation and remediation, three different heavy metal concentrations were set under the condition of 100 omega external resistance, which were group C1 (Pb 500 mg/kg, Cd 0.5 mg/kg), group C2 (Pb 1000 mg/kg, Cd 1 mg/kg), and group C3 (Pb 2000 mg/kg, Cd 2 mg/kg). The results showed that the maximum power density of MFCs in each group was 6.37 mW/m2 in group C1, 20.35 mW/m2 in group C2, and 7.49 mW/m2 in group C3, respectively. Under the condition of Pb concentration of 500 mg/kg, the remediation efficiency of Pb in soil is the highest, which is 13.58%; under the condition of Pb concentration of 1000 mg/kg, the total remediation efficiency of Pb in soil is the highest, which is 128.80 mg/kg. Under the condition of Cd concentration of 0.5 mg/kg, the repair efficiency of Cd in soil was the highest (47.52%), and the total repair amount was also the highest (0.353 mg/kg). According to the analysis of bacterial population structure, the relative abundances of Blastocatellia, Rhizobiales, and Blastocatellaceae were significantly increased in C2 group, which had the best electrical production and the highest total amount of heavy metal repair. In addition, three electrogenic bacteria in the anode chamber, including Acinetobacter oleophilus WYB1, Microbacterium levosaccharides WYB2, and Acidophaga delft WYB3, have been isolated and identified.