The Carbon Based Bimetallic Composite Catalyst For PMS Activation And Degradation Of ATZ

At present,non-point source pollution of water has become the main cause of pollution in the Yangtze River and the Yellow River in China,among which the use of pesticides in agricultural production is one of the main inducements.As one of the most widely used herbicides in China,atrazine（ATZ）has been detected in the natural environment such as water and soil,which seriously threatens the ecosystem and human health..Therefore,it is necessary to adopt reasonable methods to solve the problem of ATZ pollution in water.Conventional water treatment technology is difficult to remove water of ATZ.Advanced oxidation technology is the key to solve the pollution of ATZ.Persulfate advanced oxidation technologies because of oxidation ability,environment friendly,safe and stable,by alkali,heat,transition metal and carbon materials after activation treatment,has a good application prospect.Cation exchange resin has the characteristics of large output,low price and good ion exchange performance.After the exchange of iron and cobalt ions by cation exchange resin,the carbon base bimetallic composite catalytic material Fe_xCo_y@C is formed by calcination at high temperature,and the activated persulfate can efficiently degrade organic pollutants.In this study,Fe₁Co₂@C/PMS system was constructed to degrade the pollutant atrazine（ATZ）,providing theoretical and technical support to solve the problem of ATZ pollution,and providing a technical solution for the reuse of cation exchange resin containing heavy metals.Specific research contents and results are as follows:（1）Preparation and characterization of carbon-based bimetallic composite catalytic materials.Using cation exchange resin to prepare carbon material,using its ion exchange ability to load the iron cobalt bimetallic,after high temperature carbonization preparation of composite catalytic material Fe_xCo_y@C.The surface morphology,crystal structure,element valence state and functional group of the material were characterized by XRD,SEM,TEM and XPS.The results show that the surface of the catalytic material Fe_xCo_y@C is smooth and compact,and iron and cobalt exist in the form of metal sulfide.The valence states of Fe and Co on the surface of the material are+3,+2 and+2,and the polyvalent metal elements are favorable conditions for the activation of PMS.（2）Fe_xCo_y@C/PMS system showed a good degradation effect on ATZ.When the calcination temperature is 600℃and the ratio of Fe to Co is 1:2,the catalytic material has the best performance of activating PMS.The optimal reaction conditions were Fe₁Co₂@C=0.2g/L,PMS=0.5mm,and all ATZ could be degraded within 40 min.The degradation effect of the reaction system is better in the alkaline rang.The presence of anions in the system inhibits the activation of PMS.The system can degrade a variety of pollutants and has wide applicability.（3）The study on the mechanism of Fe_xCo_y@C/PMS system.The active groups of the system are hydroxyl radical（·OH）and sulfate radical（·SO₄^-）.·OH and·SO₄^-can be produced on the surface of Fe_xCo_y@C by-（C-SO₃）_x-Co（Ⅱ）and the catalytic cycle between Fe（Ⅲ）,Co（Ⅱ）and PMS.According to the results of LC/MS,there are three possible degradation paths of ATZ and two final products.