Prearation Of Two Surface-imprinted Polymers Based On Metal-organic Framework And Application Of Solid Phase Extraction For Pollutants In Environmental Samples

Nonsteroidal anti-inflammatory drugs（NSAIDs）are one of the most widely used drugs in the world,which still have toxic effects on aquatic organisms at low concentration level and have potential threats to ecosystem and human health.Bisphenol A is a typical environmental endocrine disruptor,which can affect the endocrine system of organisms and threaten the reproductive health of humans and animals,and its potential toxicity has attracted the attention of many scientists.The concentration of NSAIDs,bisphenol A and other typical pollutants in environmental samples is often very low,and the matrix medium is very complex.It is very difficult to detect these pollutants directly,which must go through a complex pretreatment process.With the help of molecularly imprinted polymers with good recognition performance,the pretreatment process is greatly simplified,and the accurate analysis and detection of steroidal anti-inflammatory drugs and bisphenol A and other pollutants in complex media are promoted.Surface molecularly imprinted polymer is a kind of molecularly imprinted material polymerized on the surface of different carriers.It not only preserves the advantages of molecularly imprinted polymer,but also makes the imprinted sites distributed on the surface of the material easier to approach the target,which is conducive to the mass transfer process and effectively expands the application of molecularly imprinted materials in the field of pollutant extraction and separation.Metal-organic framework materials are porous coordination compounds which are self-assembled by metal ions as the central element and organic ligands.They have super high specific surface area.Various ligands also contribute to the grafting and modification of functional groups,making the metal-organic framework materials easy to combine with a variety of substances,and obtaining imprinted polymers with rich specific recognition sites,high adsorption capacity and fast mass transfer.However,more and more attention has been paid in the field of new surface imprinted polymer preparation.In this paper,two kinds of new imprinted polymer materials are prepared by surface imprinting in pure water medium with metal-organic framework material as carrier and ionic liquid as functional monomer respectively.The two kinds of new imprinted polymer materials are characterized by various characterization methods,the adsorption properties of the two kinds of imprinted polymer materials are explored through adsorption equilibrium experiment.The solid-phase extraction columns are made respectively for the enrichment and separation of the target substances in the actual samples.The details are as follows:1.Non-steroidal anti-inflammatory drugs,bisphenol A,molecularly imprinted technology and metal-organic framework were reviewed.The detection of non-steroidal anti-inflammatory drugs and bisphenol A were described.The advantages of the combination of molecularly imprinted polymers and metal-organic frameworks were summarized.2.A novel imprinted polymer of ZIF-67-diclofenac sodium was synthesized with ZIF-67 as the carrier,1-allyl-3-vinyltetrafluoroborate ionic liquid as the functional monomer,diclofenac sodium as the template and water as the solvent.The metal-organic framework material MIL-100（Fe）as the carrier,disphenol A as the template,1-allyl-3-vinylimidazole ionic liquid and 2-hydroxyethylmethylpropylene as the carrier A new type of MIL-100（Fe）-bisphenol A surface imprinted polymer material was prepared by using the ester as a bifunctional monomer.The molecular structure,micro-morphology,specific surface area,pore size parameters and thermal stability of the two imprinted polymers were analyzed by means of infrared analysis,scanning electron microscopy,specific surface area measurement and thermal analysis,and the specific recognition mechanism of the imprinted polymer was also studied.3.The adsorption kinetics,adsorption isotherm,adsorption thermodynamics and selective adsorption performance of two kinds of surface imprinted polymers at different temperatures were studied.The results showed that:（1）the adsorption process of ZIF-67-diclofenac sodium surface imprinted polymer(MIP_DFS)to diclofenac sodium,flunixin meglumine and nimesulide was in accordance with the pseudo second-order kinetic model and the adsorption reached equilibrium in 40-80 min.The adsorption isotherm curves conformed to Langmuir adsorption model,which belongs to spontaneous endothermic reaction.MIP_DFS has good adsorption selectivity for the target.（2）MIL-100（Fe）-bisphenol A surface imprinted polymer(MIP_BPA)adsorbed bisphenol A reached equilibrium in about 20 min.The adsorption process of adsorption isotherm curve was consistent with Langmuir adsorption model,which was spontaneous exothermic reaction.MIP_BPA had outstanging selective adsorption performance for bisphenol A.4.ZIF-67-diclofenac sodium surface imprinted polymer and MIL-100（Fe）-bisphenol A surface imprinted polymer were respectively prepared into a solid-phase extraction column(MIP_DFS-SPE,MIP_BPA-SPE).Under the optimum conditions,the target residues in water,soil and food samples were enriched and separated:（1）MIP_DFS-SPE could concentrate diclofenac sodium and its structural analogues synchronously,and the recovery rates were still over 71%after 48 times of recycling;（2）MIP_BPA-SPE could still achieve over 80%after 30 times of recycling;it showed that the two surface imprinted polymers synthesized in this paper have good specific adsorption and recycling properties.5.On the basis of the above research results,this paper analyzes and summarizes the paper,expounds the innovation of this topic,and puts forward suggestions for further research work of molecular imprinting technology based on the research results,so as to provide reference for the research in this direction.