Study On Preparation Of Porous Separation Material Based By Thiol Click Chemistry And Its Filtration Performance

With the rapid development of economic globalization,environmental problems such as industrial pollution,automobile exhaust emissions and abuse of plastics are becoming more and more serious.a large number of particulates and microplastics are discharged into the environment,which seriously pollutes the safety of the environment and threatens the health of human beings at the same time.Porous organic polymers（POPs）is a kind of covalent organic porous material,which has adjustable micro-nano pore structure and high porosity.It can use its rich micro-nano pores to achieve physical interception of particles and microplastics,so as to achieve the purpose of filtration and purification.However,most of the POPs materials are amorphous and powdered,and their processability is poor,so they have great limitations in the filtration of particles and microplastics.Based on this,this paper skillfully makes use of the characteristic that thiol-yne is easy to form membrane in sulfhydryl click chemistry,and prepares two new POPs composite membrane materials based on kapok fiber membrane,in order to solve the difficult problem of POPs powder processing.At the same time,combined with the multi-stage pore structure of POPs materials,the application of composite membrane materials in particulate matter and microplastic filtration is discussed.The main contents and results of this paper are as follows:（1）In the second chapter,two kinds of POPs materials（POP-1 and POP-2）were prepared by thiol click chemical reaction using 1,3-benzenedithiol and 1,4-benzenedithiol with 1,4-diethynylbenzene.POP-1 and POP-2 have rich multi-stage pores,and their porosity reached by 66.57%and 87.28%,respectively.Based on the porous structure of POPs,POP-1/kapok fiber composite membrane material（PCM-1）was prepared by thiol click chemical reaction on the base of kapok fiber membrane.PCM-1 has excellent（PM）filtration efficiency of particulates,and the filtration efficiency of PM_2.5 and PM₁₀can reach 99.80±1.58%and 99.89±0.89%,respectively within 30 hours,which is much higher than that of kapok fiber membrane(the filtration efficiency of PM_2.5 and PM₁₀ is less than 1%).In addition,PCM-1 also showed efficient separation performance for microplastics,the filtration efficiency reached 86.93%using polypropylene fluorescent microspheres（with a particle size of 0.1μm）as the filtering object.（2）In the third chapter,by regulating the structure of alkynyl monomers,POPs/kapok fiber membrane composite membrane materials（PCM-2）were prepared by thiol click chemical reaction on kapok fiber membrane substrate,using 1,4-benzenedithiol and 1,3,5-triethynylbenzene as monomers.PCM-2 has good flexibility and multi-stage pore structure,and the porosity is 47.63%.Due to the loading of POPs material,PCM-2 showed excellent retention of PM and microplastics,and the filtration efficiency of PM_2.5 and PM₁₀ was as high as 99.90%±0.42%and 99.93%±0.26%within 30 hours,respectively.The filtration efficiency of polypropylene fluorescent microspheres with a particle size of 0.1μm is 90.92%,which is much higher than that of kapok fiber membrane（12.87%）.In conclusion,using sulfhydryl click chemistry preparation of porous composite membrane materials with abundant porous structure,good flexibility and mechanical strength.It not only provides a new opportunity for the rational design and preparation of novel functional porous composite membrane materials based on click chemistry,but also provides a new idea for its application in the field of particulate matter and microplastic filtration.