rGO/Ag复合修饰电极的微生物燃料电池对五氟磺草胺的降解效果

Effects of microbial fuel cell electricity with rGO/Ag composite modified electrode on degradation of penoxsulam

为研究微生物电池在浓药降解方面的应用,以纳米银(rGO/Ag)复合修饰/石墨毡(graphite felt,GF)电极作为阳极,研究双室微生物燃料电池(microbial fuel cell,MFC)的产电性能及其对五氟磺草胺降解的影响。结果表明:以Desulfovibriode sulfuricans为产电菌,初始五氟磺草胺质量浓度为10mg/L时,经rGO/Ag复合修饰MFC的GF阳极后,MFC的产电性能及对五氟磺草胺的降解作用皆有所提高,其中,分别以GF电极和rGO/Ag/GF复合电极为阳极时,MFC的双电层电容量分别为1.46×10^(-3)和3.85×10^(-3)mF,电子转移阻抗分别为114和61Ω,五氟磺草胺降解率分别为53.6%和67.3%。改变初始五氟磺草胺浓度和酸碱度可以影响MFC产电性能和五氟磺草胺降解作用,初始五氟磺草胺浓度为5 mg/L时,MFC的最大功率密度和五氟磺草胺的降解率分别为136.8 mW/m^(2)和70.5%,但随着初始五氟磺草胺浓度增加,其产电性能和降解作用会受到一定程度的抑制。初始酸碱度为弱碱性和中性条件时,MFC的产电性能及降解作用较高,其功率密度和降解率分别145.5 mW/m^(2)和71.4%,研究表明,MFC可以利用五氟磺草胺作为燃料,在降解的过程中同时产生电能。研究结果可为实现五氟磺草胺高效降解的同时提高MFC产电性能提供理论依据。

Biogeobattery is a natural phenomenon in which biotic processes generate electrical currents within a redox interface on the surface of the earth.The biogeobattery is caused by microbes driving electrons flow that is coupled to spatially separated biogeochemical processes.The herbicide penoxsulam is common used in paddy field.The herbicides into the soil will simultaneously occur in a series of physical,chemical and biological reactions,which may ultimately alter their ecological toxicities.This project will focuse on the effect of biogeobattery on the environmental degradation behavior of herbicide penoxsulam in paddy soil.The research starting point is produced from the electrochemically-activity of electricigenic bacteria,the mineralization and electron transfer capacities of dissolved organic matter(DOM),and the dissimilatory iron reduction and sulfate reduction in a soil microbial fuel cell.The study main line is performed on the pathways of biological and chemical transformation of herbicide,and the electron transfer mechanisms for the herbicide degradation by the paddy field microbial fuel cell(PFMFC).The associated bridge is established by the reactions of herbicide electrocatalytic oxidation and bioelectrochemical degradation in soil under the biogeobattery effect.Based on above these research results,the connections between the biogeobattery effect and the transformation of herbicide in soil are constructed,and the mechanisms that biogeobattery mediated biotic and abiotic degradation of the herbicide are proposed by the identification of intermediate and final products of penoxsulam degradation.This study investigates the electrochemical performance and its effect on degradation of pentachlorophenol using a dual chamber microbial fuel cell(MFC)with rGO/Ag composite modified graphite felt(GF)as anode.It was found that,with desulfovibriode sulfuricans as the electroproducing bacterium and the initial concentration of pendimethalin at 10 mg/L,the electroproduction performance of MFC and its degradation of pendimethalin were improved after rGO/Ag composite modification of the MFC’s GF anode,of which,when the GF electrode and the rGO/Ag/GF composite electrode were used as the anode,the bilayer electroproduction performance of MFC and the degradation of pendimethalin were improved,respectively.When the GF electrode and the rGO/Ag/GF composite electrode were used as the anode,the bilayer capacitance of MFC was 1.46×10^(-3) and 3.85×10^(-3) mF,the electron transfer impedance was 114 and 61Ω,and the degradation rate of pendimethalin was 53.6%and 67.3%,respectively;the change of the initial concentration of pentaflumuronium and the pH value could affect the MFC power generation and the degradation effect of pendimethalin.The maximum power density of MFC and degradation rate of pendimethalin were 140.4 mW/m2 and 70.5%,respectively,but with the increase of initial pendimethalin concentration,its power production performance and degradation would be suppressed to a certain extent;when the initial pH value was weakly alkaline and neutral,the power production performance and degradation of MFC were higher,with power density and degradation rate of 136.54 mW/m^(2) and 64.9%,respectively.It was shown that the MFC could utilize pentaflumizone as a fuel and generate electricity in the process of degradation at the same time.The research results will provide a scientific basis for the potential environmental risk assessment of herbicide,the ecological function and utilization of biogeobattery,and the in-situ remediation of herbicide contaminated soil.