| Microbial fuel cell is a kind of new energy technology,which uses microbial degrading organic compounds in water to generate electric and provides a new method for the utilization of sewage resources.Anode enriches microbial and determines the performance of microbial fuel cell to a great extent Anode composite support material could improves the hydrophilicity and biocompatibility of the electrode surface,providing suitable living environment for microbial as well as promoting the electron transfer between microbial and electrode,finally improving the power output of microbial fuel cell.In this thesis,the effects of MnFe2O4,immobilized ionic liquids and polydopamine-reduced graphene oxide modified materials on anode properties were studied with carbon felt as anode matrix material in order to improve the power output and waste water treatment capacity of microbial fuel cell.The following research results have been achieved:The carbon felt anode with different amount of MnFe2O4 modificated was prepared.The results showed that the power density was 414 mW/m2 at MnFe2O4 loaded with 1 mg/cm2 and the COD removel rate was 84.6 ± 6.0%.The results of cyclic voltammetry,AC impedance and Tafel curve showed that MnFe2O4 modified anode has capacitance characteristic,the bioactivity and kinetics activity was increased,the resistance of charge transfer was decreased,and the biomass of the electrode surface was increased.Decreasing the areas of anode electrode,result in the biomass was reduced,operating time was shortening in each cycle,the maximum voltage was decreased,but the power density was increased.Smaller anode area could has a higher biological activity and waste water treatment efficient after electrochemical testing and waste water treatment capacity analysis.After 6 months operation,MnFe2O4 modified anode with 2 cm2 gained the power density of 1918 mW/m2.Ionic liquids with different anions were coupled on the surface of Fe3O4@SiO2 to obtain CFe3O4@SiO2-IL anode electrode.At stable operation time,the maximum power density of Control reactor arrived 2117 mW/m2.The silicon hydroxyl groups on Fe3O4@SiO2 could form hydrogen-bond to the microbial,so the maximum power density increased to 2621 mW/m2.The electrode surface of immobilized ionic liquid modified anode was hydrophilic,the Zeta potential were changed to positive,the electrode conductivity,biocompatibility,biological activity were improved and anodic polarization was reduced.According to the scanning electron microscope result,biomass obviously improved on the inoic liquid modified anode surface.The power density of immobilized ionic liquid modified anode reactor with anionic BF4' was 3682 mW/m2 and the COD removel rate was 84.6±4.0%.The electropolymerization of dopamine on the surface of carbon felt to obtain C-PDA anode electrode.The surface of the polydopamine-modified anode was completely wetted after dopamine polymerized 80 cycles as well as introduced nitrogen-containing functional groups.The biocompatibility and the efficiency of extracellular electron transfer were improved,power density increased from 1825 mW/m2 of Control to 2475 mW/m2.The surface functional groups and Zeta potential were changed after protonation induction of polydopamine.The electron transfer resistance between microbial and electrode was reduced to 6.6 ?,the maximum power density increased to 2042 mW/m2.The inhibiting effect of oxygen-containing groups on the microbial and the charge transfer resistance could decreased after electropolymerization of dopamine on the surface of carbon felt with reduced graphene oxide to obtain C-PDA-rGO anode electrode,.the power density increased to 2990 mW/m2 after the coordinated modification with dopamine and reduced graphene oxide,and then the maximum power density increased to 3203 mW/m2 and the COD removel rate was 87.0±3.7%after protonation induction.This work provided a new development idea and reference for the modification and strengthening of the anode electrode support of the microbial fuel cell. |
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