Design,Synthesis And Application Of Multifunctional Organic Porous Materials In The Field Of Environmental Remediation

The excessive carbon dioxide emission has caused various environmental problems,such as greenhouse effect and extreme weather,greatly affecting our living conditions.What’s more,the pollution of heavy metal ions has threatened our health.Therefore,it is urgent to handle these pollutants in a simple,economical,and green way.Recently,the method of porous material adsorption is recognized as the most effective and economical method to deal with environmental pollutants.Featuring high Brunauer-Emmett-Teller（BET）specific surface area(S_BET)and pore volume(V_total),unique porosity,as well as abundant functional groups,Porous Organic Polymers（POPs）have been widely used in energy storage,catalysis,pollutant removal,and gas storage.Therefore,it is of great significance to construct multifunctional POPs to capture CO₂ and remove heavy metal ions.In this paper,a series of carbazole-based organic molecular building blocks were rationally designed and prepared to synthesize polycarbazole porous materials with specific functions under the condition of Fe Cl₃ as a catalyst,and their applications in the fields of CO₂ adsorption and catalytic conversion were studied.Through the Schiff base reaction,a 2D covalent organic framework COFs material was constructed,and its performance in the detection and adsorption of heavy metal Pd²⁺ions was explored.Besides,characterizations were carried out on the structure of the above-mentioned synthesized small molecule compounds and porous materials.The main contents of this article are as follows:In the second chapter,a bifunctional catalyst（CPBrs）polymerized by carbazole-substituted metalloporphyrin and quaternary phosphonium salt was prepared,and studied its catalytic performance for the adsorption and conversion of CO₂.In the catalytic system,zinc porphyrin（Lewis acid）and quaternary phosphonium salt（nucleophile）are used as active sites,and they can act synergistically to improve the efficiency of the CO₂cycloaddition reaction.At the same time,CPBrs（CPBr-1 and CPBr-2）are microporous polymers with permanent microporous pore structure and high specific surface area(342and 370 m²g^-1).Their capacity to capture carbon dioxide is 5.76 and 8.81 wt%（1 bar/273K）.The highest yield of the corresponding methyl-substituted propylene oxide and carbon dioxide catalyzed cycloaddition reaction can reach 95%（2.5 MPa,90℃）,which is much higher than that of other single-component catalysts.Importantly,the porous nature of the catalyst provides the reusability of the catalyst,and the efficiency of the CPBr-2 catalyst remains above 90%after five cycles of catalysis.In Chapter 3,we synthesized allyl-functionalized acylhydrazone 2D COFs（XB-COF）by solvothermal method to enable selective fluorescence detection of Pd²⁺in water（the minimum detection concentration is 0.29μM）.The stable hydrazone bond structure and the complexing ability of allyl groups with Pd²⁺enable XB-COF to maintain a good fluorescence sensing effect in both acidic and alkaline solutions,and the adsorption capacity of Pd²⁺is as high as 120 mg/g.During the interaction between XB-COF and Pd²⁺,part of Pd²⁺can be reduced to Pd nanoparticles with a particle size of about 10 nm.