The electrode strategy and its coordination mechanism in constructed wetland-microbial fuel cell (CW-MFC): a review

The electrode played an essential role in the operation of CW-MFC system due to its synergistic effect, and the development of electrode strategy has promoted the application of CW-MFC since 2012. In this paper, according to the material and the quantity, the electrode types in CW-MFC were distinctly divided into unified model, composited model, modified model, and multi-electrodes model combined with non-conductive or conductive particle. Different electrode strategies were provided to improve the performance of CW-MFC towards electricity generation, removal of pollutants, and control of greenhouse gas emission, and the coordination mechanism was further reviewed. Furthermore, the development process of the electrode strategy was summarized, and the low-cost, sustainable, and innovated electrode materials were emphatically recommended. For the scale-up application, multi-electrode model was systematically reviewed based on the optimizing of the material, shape, spacing distance, and connection type of electrode. This review may provide guidance to maximize the advantages of CW-MFC applications. Graphical Abstract