The project uses microbial fuel cells to remove heavy metal ions from soil, including lead (PB), chromium (CR), cadmium (CD), mercury (Hg). Microbial fuel cell (MFC) technology uses the electricity producing bacteria in the anode chamber to produce electrons and protons in the process of organic matter metabolism. The electrons are transferred from the anode plate to the cathode plate through the external circuit, and the protons are transferred from the anode chamber to the cathode chamber through the salt bridge, thus forming a closed loop. In this process, the heavy metal ions in the soil near the cathode plate move and enrich from the distance through the attraction of electrons, and form the elemental substance through the redox reaction on the electrode plate, so as to enrich on the cathode plate. After the operation, the cathode plate is taken out from the soil, so the heavy metal accumulated on the cathode plate is removed from the soil.
The significant difference between this technology and the current heavy metal removal technology in soil is: the current common soil heavy metal removal technology includes in-situ fixation method and translocation method. The in-situ fixation method is to fix the heavy metal ions in the soil, while the translocation method is to excavate the soil and move it to other places, then wash the heavy metal ions from the soil to the water, and then treat the heavy metals in the water Removal of ions. The technology of this project is to remove heavy metal ions directly from the soil, which has significant advantages in terms of removal effect, investment and operation cost.