Hetergenous Catalysts In Persulfate Based Fenton-like Reaction: Synthesis And Application For The Degradation Of Organic Pollutants In Wastewater

Various waste water discharged from industry contains highly toxic products,which which not only cause great harm to the ecological environment,but also seriously threaten human health.Among various environmental remediation processes,advanced catalytic oxidation technology（AOPs）is widely researched and used due to its highly efficient mineralization ability.The Fenton-like reaction based on persulfate is one of the important types of AOPs.Due to its unique advantages such as high reactivity and strong oxidation ability,it has caused extensive research by scientific researchers in recent years.This thesis aims to synthesize a heterogeneous catalyst for persulfate Fenton reaction and apply it to the degradation of organic matter in wastewater.The main research content and results of the thesis are as follows:1.Nitrogen doped porous carbon cage materials are successfully synthesized through the combination of chemical vapor deposition（CVD）and carbide-derived carbon（CDC）when using molybdenum carbide（Mo₂C）as the self-removing template,pyridine as the carbon and nitrogen source,carbon tetrachloride as the carbide etchant and carbon source through subsequent Na NO₃ activation.In terms of catalyst performance testing,5 mg of catalyst and 0.1 g of PMS were added in the system,100ml of 20 ppm phenol solution was completely degraded within 20 minutes,showing excellent catalytic performance.In the aspect of exploring the catalytic mechanism,the free radical quenching experiment,EPR,LSV,EIS test and DFT calculations proved that the pore-creating engineering by Na NO₃ could adjust the doping mode of N elements and alter the PMS-based oxidation from a radical pathway to a non-radical dominated process.According to the above work,we synthesized a nitrogen-doped porous carbon cage catalyst with excellent catalytic performance and discussed the transformation of PMS activation mechanism,which provides a new sight for the non-metallic catalytic PMS activation process.2.Supported copper-based catalyst with high catalytic activity was synthesized by impregnation-precipitation-decomposition method.Compared with the simple decomposition of nitrate,the catalyst prepared by this method has more exposed active sites and higher catalytic activity.The support ofγ-Al₂O₃ plays a dual role which can not only be used as the support of Cu O active sites,but also promote the adsorption through the basic sites on the surface during the degradation process by adjusting the p H of solution.DFT calculation,XPS and Raman results confirmed the conversion process of Cu（II）-Cu（I）-Cu（II）in the reaction and regeneration process.The copper-based catalyst could be regenerated rapidly after simple annealing in oxygen atmosphere.Finally,quenching experiments and EPR analysis revealed the free radical and non-radical processes of PDS activated by copper-based catalysts.Through the above two works,we have synthesized nitrogen doped porous carbon cage catalysts and copper-based catalysts with excellent catalytic performance.Then,we discussed the transformation of persulfate activation mechanism,which provides a new sight for the application of persulfate-Fenton-like reaction in organic degradation and environmental remediation.