Research progress of constructed wetlands coupled with microbial fuel cells for the treatment of heavy metal wastewater

Abstract

Constructed wetland coupled with microbial fuel cell (CW-MFC) is a new technology that combines constructed wetland technology (CW) and microbial fuel cell (MFC). It overcomes the disadvantage that MFC cannot be self-contained, and can generate electric energy while treating various types of wastewater. It has broad application prospect and research significance. In recent years, a large number of studies have been carried out on the treatment of dye wastewater, salt-containing wastewater, pesticide wastewater, organic compounds wastewater and antibiotic-containing wastewater by CW-MFC, and important research progress has been made. However, the research content on the treatment of heavy metal wastewater by CW-MFC is limited. Therefore, based on the existing research, the research status of CW-MFC in removing heavy metals such as chromium, arsenic, zinc, nickel and lead was summarized from the aspects of electricity production and pollutant removal effect. The removal mechanism of heavy metals in CW-MFC was also expounded from the aspects of matrix, electrochemistry, microorganisms and plants. According to the research status and removal mechanism, it is found that the removal effect and electricity generation performance of CW-MFC on wastewater containing high-valence heavy metals (such as Cr(VI)) are better. The improved performance should be attributed to the strong oxidation property of high-valence heavy metals, which increases the redox gradient of CW-MFC, promotes the electricity generation of the system and improves the efficiency of electrochemical removal. Finally, the challenges and prospects of CW-MFC technology are discussed in order to provide a theoretical basis for its development.

Keywords

• constructed wetland
• microbial fuel cell
• cw-mfc
• electrochemistry
• heavy metals
• sewage-treatment