Graphene oxide modified electrode enhances electricity generation and heavy metal removal in photosynthetic microalgae microbial fuel cells

Improving the power generation performance and pollutant removal of photosynthetic microalgae microbial fuel cells (PMMFCs) is the key to their large-scale application. In this work, microalgae (Chlorella sp. QB-102) were used as a biocatalyst in the cathode, and foam nickel modified by graphene oxide with two degrees of oxidation was used as the electrode. The results showed that the maximum power density of PMMFCs with high oxidation degree graphene oxide modified electrode (NF-GO-H) reached 209.07 mW·m-2, which was 6 times that of PMMFCs with low oxidation degree graphene oxide modified electrode (NF-GO-L), indicating that the use of the NF-GO-H electrode can effectively improve the electrical properties of PMMFCs. Simultaneously, the NF-GO-H electrode can effectively remove Cd(II), with a capacity of 6.039 g·m-2, which is twice that of the NF-GO-L electrode. Moreover, through the synergistic electrochemical action of Chlorella sp. QB-102, a large number of hydroxyl groups can be generated to convert the adsorbed Cd(II) into a more stable Cd(OH)2 precipitate. The results of this work will further expand the application of PMMFCs in power generation and heavy metal removal.