Reviews on pollution reduction and electricity production of constructed wetland-microbial fuel cells using metal mineral matrix

In the context of ‘carbon peaking and carbon neutrality goals’, the energy consumption of wastewater treatment process has gradually been paid attention, and the chemical energy contained in the wastewater has huge development potential. Constructed wetland-microbial fuel cell (CW-MFC) technology has the dual functions of reducing pollution and generating electricity, which was considered to be a promising water treatment technology. Taking advantage of the electrochemical performance of metal mineral matrix, improving CW-MFC to enhance power generation and pollution reduction has become the focus of research. Based on introducing the operating principles, advantage and disadvantage of CW-MFC and the main influencing factors, the strengthening effects of metal minerals on CW and MFC were analyzed respectively in this review. The enhancement mechanism of CW-MFC modified by metal mineral matrix in pollutant adsorption and removal by metal redox cycle, and metal minerals played a significant role in reducing internal resistance to enhance conductivity, enriching electroactive bacteria, and establishing microscopic mechanism to improve electrochemical performance through interspecies electron transfer. We revealed the phenomenon of organic carbon fixation by metal minerals in wetland, and proposed theoretical paths for organic carbon fixation in CW-MFC. Focusing on reducing the cost of CW-MFC and improving efficiency of power generation, pollution reduction and carbon sequestration, the exploration of improving CW-MFC with metal minerals was proposed, which provides a reference for the promotions and applications of CW-MFC.