Design And Synthesis Of Functionalized Organic Polymers And Their Adsorption And Photocatalysis Studies

With the advent of economic integration,the electronic industry has become a strategic development industry of major countries in the world due to its characteristics of low consumption,no pollution and high added value.As we all know,the development of the electronics industry will produce a large amount of electronic waste,in which a large amount of precious metals may be wasted.Although the gold content in e-waste is much higher than in natural ores,the lack of reliable gold extraction technology has resulted in a serious waste of resources.Therefore,the development of innovative and cost-effective adsorbents to recover gold from this e-waste is critical for future sustainability.In addition,sulfur mustard（HD）,as the"king of poisons"among chemical warfare agents,is currently the most produced,stored and even used chemical weapon.HD is volatile,has good stability,can be stored for a long time,and has great toxicity to human body.There is an urgent need to explore suitable photocatalysts for efficient photocatalytic oxidative degradation of sulfur mustard.As one of the important energy sources for human survival,biomass materials have attracted the interest of researchers due to their renewable,low-pollution and low-cost characteristics.The production cost of biomass adsorbent is far lower than other adsorbent materials,and it has greater economic benefits for the application of gold extraction from wastewater.In addition,porous organic polymers（POPs）and metal-covalent organic frameworks（MCOFs）are gradually becoming the main materials for photocatalysis due to their high porosity,high stability,and abundance.In this thesis,bifunctional natural polymers were designed and synthesized for gold recovery from electronic waste;porous organic polymers and copper-based metal covalent organic frameworks were respectively constructed and used for photocatalytic oxidative detoxification of sulfur mustard simulant.The main research contents are as follows:1.A recovery method of Au（III）for bifunctional natural polymers adsorbents was constructed.Using natural macromolecules（dopamine,chitosan and cellulose）as raw materials,they were chemically cross-linked with tetrafluoroterephthalonitrile（TFN）through aromatic nucleophilic reaction.The cyano groups of the cross-linked products were converted into amides under alkaline conditions to obtain PDA-TFN-A,Chitosan-TFN-A and Cellulose-TFN-A,which were used to specifically bind gold in electronic waste.The adsorption capacities of PDA-TFN-A,Chitosan-TFN-A and Cellulose-TFN-A for gold were 2771.8,2680.0and 1992.0 mg/g,respectively.Various physicochemical and spectroscopic studies were employed to provide insights into the binding process,confirming the efficient adsorption and in situ reduction of gold by bifunctional natural polymers based on the interaction of amide functional groups with Au and chlorogold complexes.Through comparative analysis,the bifunctional natural polymer PDA-TFN-A was shown to have the best adsorption behavior with high adsorption capacity,selectivity,stability and fast adsorption kinetics（15 min）.Based on the synergistic effect of adsorption and reduction,this work provides a promising strategy for applying environmentally friendly natural polymers to solve environmental problems.2.A novel strategy for photocatalytic degradation of sulfur mustard simulant based on heteroatom-linked porous organic polymers was proposed.Considering how difficult it is to tune the properties of polymers at the atomic level,how to introduce rational building blocks to promote the generation of reactive oxygen species remains a challenge.Three heteroatom（O,S,N atoms）-linked porous organic polymers（POP-OZ,POP-TZ,and POP-IZ）were prepared as efficient singlet oxygen（¹O₂）photocatalysts in homogeneous media.In the photocatalytic detoxification of sulfur mustard simulant,the rapid degradation of sulfur mustard simulant can be completed in 21 min,18 min and 12 min,respectively.This is the first example of using pure organic materials without metal catalytic centers and photosensitizer molecules to detoxify sulfur mustard simulant.Through detailed structural analysis,the catalytic properties of POP-OZ,POP-TZ,and POP-IZ were systematically investigated,and the relationship between the structure and properties of these POPs,as well as the differences and key roles of heteroatoms in photocatalytic properties were revealed.This study demonstrates that efficient porous organic materials can be precisely engineered as photocatalysts,providing a promising development direction for the photocatalytic degradation of chemical warfare agents.3.A degradation method of sulfur mustard simulant based on copper complex metal covalent organic framework photocatalyst was constructed.Combining the advantages of covalent organic frameworks and metal organic frameworks,vinyl-linked sp²carbon-conjugated metal-covalent organic framework Cu-Bpy-DTP and covalent organic framework Bpy-DTP were constructed by Knoevenagel condensation reaction and were used for photocatalytic oxidation of sulfur mustard simulant for the first time.Using the single crystal of the active metal species Cu coordination molecule as the building block,it is introduced into the highly stable COF,exhibiting the balanced mixing of porosity,stability and adjustability,and realizing the self complementary characteristics between the two materials.This structural design has a large impact on its functions,including porosity,chemical stability,and catalytic activity(using Bpy-DTP and Cu-Bpy-DTP as reaction catalysts can rapidly degrade CEES（Cu-Bpy-DTP only needs to be 8 min,Bpy-DTP takes 25 min）.MCOF Cu-Bpy-DTP synergistic（adsorption-photocatalytic oxidation）detoxification has higher selectivity,faster kinetics and better reusability.This study connects the advantages of covalent organic frameworks and metal organic frameworks,and provides a new idea for the rational design of metal covalent organic frameworks and the application of photocatalytic degradation of sulfur mustard simulant.