Oxidation Kinetics Of Phenols By Nonradical Activation Of Peroxymonosulfate In The Presence Of CuOMgO@Fe₃O₄ And Application

With the development of the economy,the direct discharge of wastewater from living,industrial,agricultural and medical makes the water go far beyond its self-purification ability,which caused serious pollution to the ecological environment.Organic phenol is the most common pollutant,it not only pollute the environment,also pose a threat to human health.Traditional methods of treating phenolic compounds usually do not have effectively to remove them,let alone new types of contaminants.The advanced oxidation processes based on persulfate in treatment of contaminants usually produces SO₄^?-.But the radicals are greatly influenced by various factors in the environment.In natural water,it may preferentially react with various anions without effectively to degrade the contaminants.Therefore,it is still necessary to develop a new type of oxidation system which is less affected by the environment to degrade organic pollutants.Under the previous work of the group,a new heterogeneous Catalyst CuOMgO@Fe₃O₄was prepared by incorporation of MgO to the inert catalyst CuO@Fe₃O₄ by co-precipitation methods,and the specific surface area,morphology and crystal structure of the catalyst were analyzed by BET,SEM and XRD.In this thesis,the degradation of phenolic-pollutants by CuOMgO@Fe₃O₄ activated PMS was studies.The results showed that the catalyst CuOMgO@Fe₃O₄ has much higher activity than CuO@Fe₃O₄.A variety of phenolic-pollutants can be degraded by CuOMgO@Fe₃O₄/PMS.Chemical quenching experiments suggested that ¹O₂ rather than SO₄^?-and HO?contributed to phenolic-pollutants degradation by the CuOMgO@Fe₃O₄/PMS systems.The linear free energy relationships?LFERs?between the observed pseudo-first-order oxidation rates of various substituted phenols and the classical descriptor variables(Hammett constant???⁺??^-,half-wave oxidation potential E_1/2,acidity coefficient p K_a)were studied.It was found that the degradation rate of substituted phenols decreased with the increase of?⁺,and has poor linear with pK_a,which indicated that substituted phenols was degraded by ¹O₂ through electron transfer process,and there was no proton transfer process in the process.Based on identified degradation peoducts by GC-MS,the degradation pathway of 4-acetamido phenol,4-chlorophenol and p-hydroxybenzoic acid in CuOMgO@Fe₃O₄/PMS systems were proposed.In practical application,compared with radical system,the nonradacal system with ¹O₂ as the main active species produces less BrO₃^?,higher mineralization efficiency of organic matter,less phytotoxicity of degradation products and less influence by environmental factors.This thesis reveals the degradation pathway of¹O₂ as an active species to degrade phenolic-pollutants and applies it to natural water.This work may provides a new strategy for improving the activity of inert catalyst and has important guiding significance for the research of the advanced oxidation processes to degrade pollutants.