Self-Driven Electrokinetic Remediation of Cd Contamination Soil by Using Double-Chamber Microbial Fuel Cell

Green and sustainable techniques are in great demand for the remediation of heavy metal-contaminated soil. Cadmium ion (Cd 2+ ) in soil could be extracted under the internal electric field and participating on the surface of the electrode. Here, we proposed a sediment microbial fuel cell (SMFC) for the electrokinetic remediation of cadmium (Cd) contamination soil. Within the 7 weeks of SMFC operation, the removal efficiency for total Cd could be up to 70.04 ± 0.45%, which was significantly higher than that obtained by open circuit SMFC. The maximum output power density was 71.00 ± 0.82 mW m −2 with a current density of 0.60 ± 0.03 A m −2 . Results obtained by electrochemical impedance showed that the inter resistance of SMFC was 944 ± 14 Ω. High-throughput sequencing revealed that the Alpha-, Beta- and Gammaproteobacteria increased to 67.85%–80.99% in the SMFC. The relative abundance of Cd 2+ /Zn 2+ -exporting ATPase, participating in Cd 2+ reduction, in SMFC varied from 25.83% to 30.68%, which were significantly higher than that of control (11.21% to 19.94%). Our findings have presented an effective energy-saving method for the remediation of heavy metal-contaminated soils. Soil microbial fuel cell was capable of removing Cd efficiently. Two removing pathways of Cd 2+ were proposed. Microbially produced electric field was the driving force for metal transfer. Soil Cd 2+ could be reduced and precipitated at the cathode.