Modified Anode Microbial Fuel Cells For Treating Copper-containing Wastewater

Microbial fuel cells?MFCs?are a novel energy conversion technology that uses microorganisms as a catalyst to convert chemical energy directly into electrical energy.In order to improve copper removal and recovery,carbon nanotubes and manganese dioxide were applied to MFCs in this study.The experimental results are as follows:?1?CNTs/EG,0.02gMnO₂/CNTs,0.03gMnO₂/CNTs modified anode were prepared.After the electrode was modified,XRD and FTIR tests show that manganese dioxide and carbon nanotubes are successfully attached to the electrode.SEM test showed that the surface of the modified anode became rough.The surface wettability test showed that the surface contact angle of the electrode was reduced,The surface contact angle of the CNTs/EG modified electrode is at least 11.17°.The cyclic voltammetry curve showed that the electron transfer rate of the modified electrode was accelerated,and the AC impedance test showed that the internal resistance was reduced small,where in the ohmic internal resistance of the CNTs/EG electrode is at least11.89?,and the charge transfer internal resistance is at least 276.8?.?2?The modified electrode was used as anode in MFC.The maximum output voltages of graphite anode,CNTs/EG,0.02gMnO₂/CNTs and 0.03gMnO₂/CNTs modified anode were 0.44V,0.58V,0.61V and 0.67V,respectively.The maximum power density is 184.39mW/m²,561.09mW/m²,893.47mW/m²and 1044.21mW/m²,respectively.The maximum power density is increased by 204.30%,384.55%and466.31%,respectively,compared with the unmodified anode.The removal rates of copper in the cathode chamber were 65.73%,92.58%,98.63%and 98.93%,respectively.and the removal rates of copper were increased by 40.85%,50.05%and50.51%,respectively;It shows that the modified anode improves the electricity production performance of MFC and the removal rate of copper-containing wastewater.The XPS test showed that Cu₂O were detected at the cathode.Analysis of the anode chamber microbial community by high-throughput sequencing,The results showed that the main genus was Syntrophomonas,Aminobacterium and Leptolinea.?3?0.03gMnO₂/CNTs modified electrode was applied to MFC treatment of different concentrations of copper-containing wastewater.The Cu²⁺concentrations were 100mg/L,300mg/L,500mg/L and 700mg/L,respectively.The removal rates were98.8%,99.22%,99.66%and 98.31%,respectively.the remaining concentrations were1.2mg/L,2.35mg/L,1.7mg/L,11.85mg/L.Moreover,the higher the ratio of electron acceptor(Cu²⁺)to electron donor?sodium acetate?,the less copper ions are reduced.the XPS test showed that the cathode reduction products were Cu₂O and elemental copper.Analysis of the anode chamber microbial community by high-throughput sequencing,which the results showed that the main genus was Aminobacterium,Sedimentibacter,Lysinibacillus and Anaerolinea.