Performance And Mechanisms Of CuO And Its Compounds In Activating PMS For Degradation Of Organic Contaminants

The discharge of a large number of non-biodegradable pollutants poses a serious threat to the environmental ecosystem,and it is urgent to develop new advanced treatment technologies.The persulfate advanced oxidation technology shows great advantages in the degradation of organic pollutants due to its strong oxidation ability,mild reaction conditions and wide range of application.Therefore,this study prepared CuO as persulfate activator,and constructed CuO composite materials that are easy to solid-liquid separation.The performances and mechanisms of CuO and its compounds on degradation of organic contaminants through peroxymonosulfate（PMS）activation were researched.And the influences of various factors such as catalyst dosage,PMS dosage,initial pH values,temperature and co-existing anions as well as natural organic matters in the solutionon on the degradation of pollutants were investigated.The main findings were listed as follows:（1）The nano CuO catalyst with a spindle shape was synthesized by simple hydrothermal method.The morphology,valence and crystal structure of CuO were characterized by XRD,XPS,SEM,TEM and other means.The experiment showed that the nano CuO nanoparticles have a strong ability to activate PMS to generate active species,and the CuO/PMS system has a good performance in the degradation of methylene blue（MB）,methyl orange（MO）and tetracycline hydrochloride（TC）.The effects of CuO dosage,PMS concentration,initial pH value of solution and reaction temperature on the catalytic activity of the system were investigated.The experiments showed that CuO/PMS system remain good efficient in different environments,such as different pH value from 4 to 12,different water bodies including deionized water,tap water,lake water,and the coexistence of environmental anions（HCO₃^-、NO₃^-、Cl^-）and humic acid.According to the free radical capture experiments,the active species of the CuO/PMS system for the degratation of MB are¹O₂、O₂^·-、·OH、SO₄^-·,and ¹O₂andO₂^·-played a decisive role.（2）CuO@MnO₂nanoparticles were prepared by a simple hydrothermal method,and CuO@MnO₂nanoparticles were loaded on the surface of cellulose acetate（CA）to build CuO@MnO₂@CA composites,which are easy to separate from the solution.The morphology,valence and crystal structure of CuO@MnO₂@CA were characterized using XRD,XPS,SEM,TEM and other means.The results showed that CuO@MnO₂were loaded uniformly and firmly on the CA.CuO@MnO₂@CA composites had excellent capability on the degradation of MB,MO and TC,and satisfactory performance in the cyclic test.The effects of CuO@MnO₂dosage,PMS concentration initial pH value of solution and reaction temperature on the catalytic activity of the system have been investigated.The experiments showed that CuO@MnO₂/PMS system remain good efficient in different environments,such as different pH value from 4 to 12,different water bodies including deionized water,tap water,lake water,and the coexistence of environmental anions(Cl^-、NO₃^-、H₂PO₄^-、SO₄^2-).The free radical capture experiment confirmed that the active species of the CuO@MnO₂/PMS system for the degratation of MB are ¹O₂、O₂^·-、·OH、SO₄^-·,and¹O₂andO₂^·-play a decisive role.（3）CuO@Fe₃O₄composites had been successfully prapared through a hydrothermal method,thich are easy to separate from the solution with the help of external magnetic force.The morphology,valence and crystal structure of CuO@Fe₃O₄were characterized by XRD,XPS,SEM,TEM and other means.CuO@Fe₃O₄composites had good capability for PMS activation to degrade pollutants,such as MB,MO and TC.The cycle test proves that CuO@Fe₃O₄/PMS system has stable performance in the degradation of MB.The effects of CuO@Fe₃O₄dosage,PMS concentration,initial pH value of solution and reaction temperature on the catalytic activity of the system were investigated.The experiments showed that CuO@Fe₃O₄/PMS system remain good efficient in different environments,such as different pH value from 4 to 12,different water bodies including deionized water,tap water,lake water,and the coexistence of environmental anions(Cl^-、NO₃^-、CO₃^2-).The free radical capture experiment and ESR spectra confirmed that the active species of the CuO@MnO₂/PMS system for the degratation of MB are ¹O₂、O₂^·-、·OH、SO₄^-·,and¹O₂andO₂^·-play a decisive role.