Research On Preparation Of Gas Diffusion Electrode And Its Performance For Degradation Of Phthalate Esters

With the rapid development of economic production, it is inevitable to release toxic refractory organic pollutants for environment, such as phenol, phenol, chlorine pesticides, PCBs, PAHs, nitro aromatic compound, dye, and so on. These pollutants have complex component, some of them have teratogenic, organic pollutants carcinogenic, mutagenic for people, such as phthalate ester. Because the conventional wastewater treatment methods can’t effectively deal with toxic refractory organic pollutants, Advanced oxidation technologies which are based on producing strong oxidizing agent(hydroxyl radical,·OH) become a focus of study in recent years.Electric-Fenton method is a new advanced oxidation technology, compared with other conventional method, it has following advantages:one is perfect automatic producing H2O2mechanism; The other is A variety of oxidation degradation organic approach, not only by·OH. However, Electric-Fenton method is at low current efficiency, Fe2+is not easy to be reduced by Fe3+, and the cathode materials are not very good for Electro-Fenton reaction, so the use of Electro-Fenton is limited.Based on the study of predecessor, aim to solve the problem of Electro-Fenton method, this paper study the situation of phthalic acid ester (PAEs) degradation, and dimethyl phthalate (DMP) will be the representative. Using different electrodes (graphite rod electrode, carbon fiber electrode, foamed nickel electrode, Vulcan XC-72carbon electrode) as Electro-Fenton cathode, comparatively study the performance of them. The results show that foamed nickel electrode and Vulcan XC-72carbon electrode performed the best in Electro-Fenton system, both of them are good at catalysis for O2reduction.In the experiment, we use three electrodes device for reactor, foamed nickel electrode is made for Electro-Fenton cathode, using chronoamperometry to study the performance of foamed nickel electrode for H2O2cumulative concentration and DMP degradation. During the experiment, we found Electro-Fenton condition have an important impact on foamed nickel electrode performance. Research shows that, at the experiment condition:Co(DMP)=50mg L-1, C (Na2SO4)=0.1mol L-1, C (Fe2+)=0.5mmol L-1, pH=3, cathode potential is-0.5V vs. SCE, Aeration rate of O2at200mL min-1, foamed nickel electrode performed best.Preparation technology of Vulcan XC-72carbon electrode is important for electrode performance. Using spraying method to prepare Vulcan XC-72carbon electrode, using scanning electron microscope (SEM) to observe micro morphology of the electrode, and using N2adsorption for specific surface area of electrode’s determination, using chronoamperometry to study the DMP degradation performance of electrode as cathode in Electro-Fenton system; Then we optimize the technological parameter of electrode preparation, such as the loading of Vulcan XC-72carbon, the content of PTFE. The results show:Vulcan XC-72carbon electrode has good performance in Electro-Fenton system, when the loading of Vulcan XC-72carbon is3.0mg cm-2, content of PTFE is20.0wt%, the electrode performed best at H2O2cumulative concentration and DMP degradation.