Preparation Of Surface Molecularly Imprinted Polymers And Their Properties In Removal And Detection Of Phenolic Compounds

In recent years,due to the development of industry and the acceleration of urbanization,the exponential growth of the population has increased the demand for agricultural and industrial products.Water pollution caused by excessive and uncontrolled emissions and increasing consumption of fresh water have caused water shortages to become Global issues.The highly toxic and carcinogens emitted from various channels can cause harm to organisms and the environment,making it a huge challenge for the government to provide clean and safe drinking water.Therefore,conducting efficient research on the removal and detection of various pollutants in water bodies has important practical significance for ensuring the safety of water quality and the health of residents' drinking water.Because molecularly imprinted polymers have specific recognition sites,they can selectively identify target compounds in the analysis and detection of environmental pollutants in aqueous media.Its excellent recognition characteristics are derived from the interaction between the template molecules and the monomer functional groups present in the pre-polymerized complex formed by the functional monomers.When molecularly imprinted polymers meet the analytes in the sample matrix,these interactions can easily be re-established.It is this function that provides molecularly imprinted polymers with significant advantages over traditional non-selective adsorption and enrichment agents.Its excellent performance reduces interference and matrix effects during sample preparation,enabling highly selective and accurate analysis.In this paper,two molecularly imprinted polymers with different responsiveness are designed and synthesized to remove and detect pollutants in water.The specific research contents are as follows:(1)A novel surface molecularly imprinted polymer was constructed using magnetic mesoporous titanium dioxide as a carrier for the selective removal of tetrabromobisphenol A(TBBPA).First,Fe3O4 nanoparticles were prepared by a solvothermal method,and Fe3O4@SiO2 was prepared by a sol-gel method.Then,a mesoporous TiO2 layer with a large specific surface area was constructed on the surface.This layer can provide sufficient for imprinted polymers.Recognize the site and then use azide-functionalized dopamine to non-covalently azide-functionalize it.Subsequently,the alkynyl-terminated RAFT reagent was connected to the surface of the magnetic mesoporous titanium dioxide support by a click chemical reaction between an azide group and an alkynyl group.Finally,4-vinylpyridine(4-VP)was used as the functional monomer,Alcohol dimethacrylate(EGDMA)was a crosslinking agent,TBBPA was a template molecule,and a molecularly imprinted polymer layer was introduced on the surface of Fe3O4@mTiO2 by RAFT polymerization.The effects of the amount of functional monomer 4-VP and cross-linker EGDMA on specific recognition performance were studied.The results of adsorption performance studies showed that the maximum adsorption capacity of Fe3O4@mTiO2@MIP for TBBPA was 41.67 mg g-1,which is much higher than the non-imprinted polymer Fe3O4@mTiO2@NIP(20.92 mg g-1).The results of competitive adsorption experiments show that in the presence of TBBPA and its structural analogs,Fe3O4@mTiO2@MIP still shows excellent affinity for TBBPA molecules.What's more,due to the presence of the magnetic core,the prepared imprinted polymer can be easily separated from the liquid medium to achieve the effect of repeated recycling.(2)A surface molecularly imprinted polymer ratio fluorescence sensor was constructed with SiO2 as a carrier for high-sensitivity detection of bisphenol A(BPA).First,SiO2 nanoparticles with good dispersibility were prepared by the sol-gel method,then CdTe quantum dots were introduced as a fluorescence response signal.After using 3-aminopropyltri ethoxy silane as the functional monomer and ethyl orthosilicate as the crosslinking agent,imprinted polymers were prepared by cross-linking polymerization.Adsorption experiments showed that the prepared imprinted polymer showed highly selective recognition of BPA with a linear range of 1-100?mol·L-1 and a detection limit of 0.4 ?mol·L-1.When the imprinted polymer interacts with BPA again,a light-induced electron transfer effect will occur between BPA and CdTe quantum dots,so that the fluorescence of CdTe quantum dots will be quenched to varying degrees according to the concentration of BPA.At the same time,carbon quantum dots that do not participate in the reaction were added as a fluorescent reference signal during detection,so that the response signal can visually observe the color change under the contrast of the reference signal,which can easily and sensitively detect BPA in water.