| In recent years, for the difficult degradable organic pollutants in water removal has become a research hotspot in the field of water treatment, which has a broad spectrum treatment effect and high efficiency, easy operation, and environment friendly advantages of advanced oxidation technology has attracted wide attention of researchers at home and abroad. E-Fenton method is the essence of the electricity produced by the chemical method of H2O2and (or) Fe2+as a continuous source of Fenton reagent and constantly added. Which exist in acid medium and Fe2+system, the use of O2in the cathodic reduction reaction with Fe2+and H2O2generated hydroxyl free radical (·OH) produced by the oxidation of organic matter. Field produced with electric-Fenton method of H2O2and H2O2compared to the traditional Fenton method has significant advantages:(1) avoid the potential risks in H2O2transportation and storage process;(2) H2O2and Fe2+continues to produce, at a rate can guarantee long sustained efficient degradation, oxidation of organic matter can get more completely, and less sludge production;(3) E-Fenton reaction to remove organics organic factors is more, in addition to the oxidation of the·OH, anodic oxidation, adsorption, etc.This paper with high surface area activated carbon fiber (ACF) as the cathode, the shape stability of RuO2/Ti electrode network as anode, using the quasi three dimensional structure of activated carbon fiber strengthening cathodic indirect oxidation, using the electricity-Fenton method to study the degradation of organophosphorus pesticide glyphosate, obtain the following main results:1、H2O2on activated carbon fiber cathode electrochemical process has carried on the system research, some influencing factors, such as current intensity, initial pH, ventilation flow rate and gas species effects on H2O2generated in the background. The experimental results show that the greater the current intensity, the more H2O2produced by; Acidic condition is advantageous to the H2O2generated; Ventilation flow mainly influence the mass transfer process of the reaction, the gas flow rate, the greater the H2O2produced by more, but when the gas flow rate is increased to a certain extent, its effects on H2O2production is not very obvious; Background gas species effects on H2O2generation from high to low in turn to oxygen, no gas, air, nitrogen, which under the condition of no gas bubbled into generating H2O2than going into the air when H2O2generation, shows that oxygen produced by reaction of anode can provide oxygen cathode; The study also found that H2O2generated is proportional to the water dissolved oxygen concentration; 2、ACF cathode-Fenton reaction can efficiently degrade pesticide glyphosate, at pH3.0, current under the condition of0.36A and Fe2+1.0mM with0.5mM (84.5mg/L) glyphosate360min, glyphosate concentration removal rate can reach more than84.4%, the TOC removal rate reached48.5%. ACF as cathode electricity-Fenton reaction of glyphosate in water TOC removal rate is significantly higher than that of single anode oxidation (TOC removal rate was2.7%) and H2O2electrochemical process (TOC removal rate as20%). ACF cathode the optimum pH of around3.0; The strength of the current increase for degradation of organic compounds; Ferrous ion concentration increase can increase the TOC removal, but Fe2+concentration is too high will make processing efficiency because of Fe2+to capture the·OH. Untreated glyphosate solution completely not biochemical degradation (BOD5/COD=0), the electric-Fenton reaction processing after360min, BOD5/COD increases to0.32, show that this method has gained strong wastewater biochemical availability, combined with biochemical method can be used as a pretreatment process, can effectively increase the system processing efficiency, reduce processing costs;3、For electricity-Fenton reaction mechanism were studied, using DMSO and Fast Blue BB Salt method detection system generated in the·OH, the results show that the electricity-Fenton reaction have a high concentration of·OH in Fenton system generated; Compared the iron ion valence has certain influence of·OH, Fe2+to produce free radicals concentration is Fe3+high; Current strength for electricity, metal ion type, gas type have certain effect on E-fenton reaction;4、This thesis is the transformation of electric iron ions in clarified E-Fenton system was studied, the results show that ACF can be effective electrochemical reduced iron ion, and can make the system of Fe2+cycle, guarantee the degradation efficiency of organic matter. Current intensity, the types of gas are influence on iron is the original one; Current intensity, the greater the reduction of iron ions is less, this is because with the increase of current intensity, anode oxidation as also gradually increase, anodic oxidation on ACF reduction greatly, so the reduction of iron ion concentration gradually reduce; Gas species reduction of iron ions are mainly under the condition of nitrogen by reduction of iron ions concentration is highest, and under the condition of oxygen, air and no gas reduction of iron ions is not obvious, this is because the gas with nitrogen as the background, system belongs to restore system, by the reduction of iron, and other background gas oxidation system, iron reduction effect is poorer;5、Finally,this paper had been used to characterize the surface properties of ACF. In ACF using SEM observation showed that the carbon fiber surface more smooth and has obvious axial crack; Found that ACF by ASAP2000type than surface area measurement has great specific surface area, and there are many holes in the pore size of more than2nm, more than 98%of the adsorption pores and holes, narrow pore size distribution, and specific surface area of ACF treated by electric-Fenton basic no change, has the very good mechanical strength. |
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