Simultaneous Degradation Of Azo Dyes And Electricity Generation Characteristics In Microbial Fuel Cells With Titanium-based Material Electrodes

Microbial Fuel Cells(Microbial Fuel Cells,MFCs)are a new type of wastewater biological treatment technology with both productivity and degradation functions.It can degrade or oxidize organic matter to release electrons to the anode by using the active microorganisms in the anode chamber and then transfer electrons to the cathode through external circuits(such as Pt wire,Ti wire,etc.),where it combines with electron acceptors(such as O2)to form water.As an environmentally friendly biological wastewater treatment technology,MFCs have great potential in solving water resource crises and environmental pollution.In this paper,titanium electrodes are used to explore their simultaneous productivity and degradation in microbial fuel cells(MFCs).First,anodic oxidation was used to prepare titanium dioxide nanowires,and different types of nanoparticles were doped to prepare composite electrodes by electrodeposition.Secondly,the electrochemical characteristics of doped electrodes and the degradation performance of the applied MFCs system were investigated respectively.Finally,the production mechanism and the photodegradation performance of dye wastewater were analyzed,and the dual-chamber degradation of microbial fuel cell power utilization were explored.The main research contents and results are as follows:(1)The titanium dioxide nanowire photoelectrodes were prepared and used as the cathode to be placed in the microbial fuel cell reactor.When the TiO2 NWs cathode is irradiated with ultraviolet light,the active scarlet is rapidly reduced and electricity is generated simultaneously.Electrochemical impedance spectroscopy(EIS)showed that the polarization resistance(Rp)of the photocathode MFCs decreased from 294? in the dark to10.45? in the light,indicating that the photocatalysis of the titanium dioxide nanowires can enhance the cathode electron transfer process.The analysis of the decolorized product indicated that the azo bond of the active scarlet may be cleaved by photoelectrons at the irradiated photocathode.The electricity produced by MFCs was expected to enhance the reductive decolorization of the azo dye Active Red solution.The results showed that the titanium dioxide nanowire photoelectrode works as the cathode with the lighting and bioenergy in MFCs.(2)The titanium-based CdS photoelectrode was prepared,and the microbial fuel cell reactor containing the photoelectrode was constructed.The structure of the doped CdS electrode was characterized by SEM,XPS and XRD tests.Through the cyclic voltammetry curve,electrochemical impedance spectroscopy and other electrochemical index tests,the influence of light and dark conditions on the electricity generation performance of the titanium-based CdS cathode microbial fuel cell was analyzed.Diffuse reflectance spectroscopy showed that the CdS photocathode has extended the spectral response range and has a clear light response under visible light.The degradation experiment of methylene blue solution showed that the best degradation experiment structure is closed-circuit MFCs in light;doping with CdS expands the spectral response range of the electrode,and both photogenerated electrons and electrons transferred from the anode participate in organic reduction.In this process,the bond breakage and decolorization of methylene blue were achieved.(3)The titanium-based N-doped electrode was prepared,and its performance in generating electricity and degrading methylene blue in microbial fuel cells were studied.The surface morphology of the synthesized photocathode was characterized by SEM and EDS,and it was found that N was uniformly distributed on the electrode surface.Secondly,the electrical impedance spectrum shows that the N-doped electrode has low ohmic impedance and high conductivity,which can increase the electron transfer rate.The cyclic voltammetry curve shows that the N-doped electrode has high electrochemical activity.The LSV curve shows that the N-doped electrode has high ORR activity.Methylene blue degradation experiments show that the best degradation experiment structure is closed-circuit MFCs in light.In the paper,the dual-chamber microbial fuel cell constructed with titanium-based composite electrodes prepared by anodic oxidation and electrodeposition techniques,has good energy output and stability.The degradation performance of MFCs was explored with dye wastewater as the target pollutant,which provide a reference for the application of titanium-based materials in dye wastewater treatment combined power generation of MFCs.