Enhanced copper-containing wastewater treatment with MnO2/CNTs modified anode microbial fuel cell

A microbial fuel cell (MFC) was constructed with CNTs, 0.02gMnO2/CNTs and 0.03gMnO2/CNTs modified graphite anode prepared by coating for enhancing copper wastewater treatment. The SEM, XRD and FTIR results showed that MnO2/CNTs and CNTs were successfully attached to the graphite electrode, indicating that the electrode was modified successfully. The surface wettability test showed that the decrease of the contact angle of the modified anode led to the increase of hydrophilicity, which was more conducive to microbial adhesion. The surface contact angle of CNTs modified electrode was the smallest, which was 11.17°. The maximum output voltage, power density and copper removal rate of 0.03gMnO2/CNTs modified anode MFC were 0.67 V, 1044.21 mW/m2 and 98.93% respectively, which were 52.3%, 466.3% and 50.5% higher than those of unmodified anode. XPS results showed that the reduction products were Cu2O and Cu. Meanwhile，high throughput sequencing showed that CNTs and MnO2 could improve the richness and diversity of microbial community. MnO2/CNTs modified-anode accelerated the enrichment of electro-active bacteria such as Proteobacteria, Firmicutes and Bacteroidetes.