Preparation Of Novel Functional Materials Based On Ugi Multicomponent Reaction And Their Removal Of Typical Pollutants In Water

Environmental pollution is now one of the top three social problems in the world.Heavy metal wastewater has the characteristics of high toxicity,non-biodegradability and persistence,dye wastewater has the characteristics of large volume,high chroma,high toxicity,complex components and a wide variety of characteristics,which poses a greater threat to the ecological environment and water safety.Adsorption is one of the simplest and most effective treatment methods to remove pollutants from wastewater.Modification can improve the ability of adsorbent materials to remove pollutants,but traditional modification methods often suffer from low atomic utilization,low yield,poor stability and serious environmental pollution.Therefore,in this thesis,two new functionalized biochar and MOFs materials were developed through Ugi multicomponent reaction to improve the adsorption performance of the materials and enhance the adsorption capacity of copper ion heavy metals and methyl orange dye,the main research and results of the thesis are as follows:Preparation of polyethyleneimine functionalized biochar（BC-NH）and adsorption studies on copper ions.First,the biochar is carboxylated,and then the polyethyleneimine is compounded with the biochar through Ugi reaction to prepare BC-NH.The adsorption of copper ions on BC-NH was endothermic and spontaneous.The maximum adsorption capacity is 21.39 mg/g,which is 10 times that of the unmodified biochar.the enhanced adsorption performance of BC-NH was mainly attributed to the increase in active sites due to the introduction of polyethyleneimine.BC-NH maintained ultra-high adsorption stability in the p H range of 3-5,remained highly selective in the presence of competing ions(K⁺and Mg²⁺)and still had a good regeneration capacity.The adsorption kinetics,adsorption isotherms and adsorption thermodynamics were investigated,and the adsorption model of BC-NH on copper ions was found to compound the pseudo-secondary kinetic model and the Langmuir model.The study of the adsorption mechanism showed that the adsorption of copper ions by BC-NH was dominated by chemisorption accompanied by physical adsorption,and the combination of FTIR and XPS showed that copper was removed by chelation with the nitrogen-containing functional group amide N in BC-NH.Preparation of L-cysteine functionalized UIO-66-NH₂（UIO-66-NS）and adsorption studies on methyl orange.UIO-66-NH₂was first prepared by solvothermal synthesis,and then UIO-66-NS was prepared by compounding L-cysteine with UIO-66-NH₂via the Ugi reaction.the adsorption of UIO-66-NS on methyl orange was a endothermic and spontaneous process,and the maximum adsorption capacity was 242.72 mg/g,which is doubled compared with the unmodified one.The adsorption kinetics,adsorption isotherms and adsorption thermodynamics indicated that the adsorption model of UIO-66-NS on methyl orange was a combination of the pseudo-secondary kinetic model and the Langmuir model.In addition,UIO-66-NS exhibited ultra-high stability in acidic,neutral and basic media（p H=3-10）,and its reusability is poor.Studies of the adsorption mechanism indicate that the adsorption of UIO-66-NS on methyl orange is mainly chemical adsorption,accompanied by physical adsorption including electrostatic adsorption,hydrogen bonding andπ-πinteractions.