Preparation And Application Of Photoresponsive Dibutyl Phthalate Imprinted Polymer

Phthalate esters(PAEs)are industrial chemical products that are often used in polyvinyl chloride materials as plasticizers and are widely used in hundreds of products such as toys and food packaging materials.These compounds can enter the body through the respiratory system or skin and act like estrogen in the body,disrupting endocrines and causing health problems in humans.Dibutyl phthalate(DBP)is the most widely used phthalate in the chemical industry.Therefore,the accurate detection of DBP in the environment has become an important topic.Molecular imprinting(MIT)is a process by which biomacromolecules are transferred from a gel to an immobilized substrate,resulting in the preparation of molecularly imprinted polymers(MIPs)with specific recognition of target molecules.With the further development of technology,stimulation-responsive molecularly imprinted polymers have emerged.Due to the rapid response of polymers to external stimuli(temperature,pH and light),the recognition efficiency of MIPS for target molecules has been improved.Therefore,stimulation-responsive MIPS has become a research hotspot in the field of rapid separation/enrichment in recent years.In this paper,using dibutyl phthalate(DBP)as template molecule and 4-[(4-methylacrylloxy)phenylazo]benzenesulfonic acid(MAASA),methacrylic acid(MAA)and acrylamide(AAM)as functional monomers,three different photoresponsive MIPs were prepared by surface imprinting method.The morphology and structure of the polymer were analyzed by Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM)and transmission electron microscopy(TEM),and the performance of MIPS was evaluated.Finally,the prepared MIPS was successfully applied to enrich/separate DBP in actual samples.The specific research contents are as follows:(1)Preparation and application of dibutyl phthalate imprinted polymers based on Fe₃O₄@SiO₂-MAPASA photosensitive monomer:Photoresponsive molecularly imprinted polymers(P-MIPs)were prepared using Fe₃O₄ as carrier and MAPASA as functional monomer.The characterization results showed that the prepared P-MIPs were uniform in size and the thickness of the imprinted layer was about 10 nm.The adsorption experiments showed that it only took about 30 min and 10 min to reach equilibrium under 365 nm and 440 nm light conditions,and the maximum adsorption capacity of DBP was 3.88 mg/g.The Freundilich and Langmuir isotherm models of P-MIPs were established,and the results showed that the adsorption process was in accordance with the Freundilich model.Finally,P-MIPs was successfully applied to the determination of DBP in liquor with the recovery of 95.4-98.4%and the relative standard deviation of less than 5.6%,which indicated that P-MIPS could be applied to the determination of trace DBP in actual samples.(2)Preparation and Application of Dibutyl Phthalate Imprinted Polymer Based on SiO₂-Multifunctional Monomer:SiO₂ nanoparticles were used as carriers.After chemical modification,MAA and MAPASA were selected as functional monomers to prepare bifunctional monomer imprinted polymers(P-MIPs),and the equilibrium adsorption capacity of P-MIPs on template molecule DBP was evaluated.The results showed that the prepared P-MIPs were uniform in morphology and size,and the thickness of the imprinted layer was about 12 nm.The adsorption experiments showed that the prepared P-MIPs could specifically recognize and adsorb DBP,and the adsorption process of P-MIPs was consistent with the Freundilich adsorption isotherm model,and the adsorption capacity reached 4.45 mg/g.Finally,P-MIP_S was successfully applied to the determination of DBP in river water,the recovery was 95.8-99.2%,and the relative standard deviation was less than 4.2%,which indicated that P-MIPs could be applied to the determination of trace DBP in actual samples.(3)Preparation and Application of Dibutyl Phthalate Imprinted Polymer Based on Multi-functional Monomer Hollow Structure:Using SiO₂@VTMOS as the carrier,MAPASA and AAM as the functional monomers,EGDMA as the crosslinking agent,P-MIPs were prepared by surface imprinting method initiated by AIBN.Finally,P-MIPs were etched with 20%HF solution to obtain the hollow-structure molecular imprinted polymers(P-MIPs).Characterization results showed that the prepared P-MIPs were uniform in size and the thickness of the imprinted layer was about 33nm.Adsorption experiments showed that the maximum adsorption capacity of P-MIPs was 5.2mg/g,and the adsorption process of P-MIPs accorded with Langmuir adsorption isothermal model.In addition,the specific selection experiment proved that P-MIPs could specifically adsorb DBP.After four cycles of desorption,the polymer had no obvious loss of photoreversibility.Finally,the intelligent photocontrolled polymer was successfully applied to DBP detection in river water(riverside).The recovery rate was 83.2-80.8%,and the relative standard deviation was less than3.1%,which indicated that it could be applied to trace analysis and detection of DBP in actual samples.In summary,the preparation and adsorption performance of the photoresponsive molecularly imprinted polymers were discussed in this paper.The results showed that the prepared MIPS could concentrate and separate DBP by changing the illumination conditions,and was successfully applied to the trace analysis and detection of DBP in actual samples.