Enrichment And Detection Of Organic Pollutants By Magnetic MOF Molecular Imprinted Functional Materials

Organic pollutants are usually characterized by high toxicity,persistence and bioaccumulation.However,most of the detection methods of organic pollutants are complicated and inefficient,so it is of great significance to develop an efficient and environmentally friendly enrichment detection method for organic pollutants.This study designed two types of magnetic functional materials pretreatment methods,one is the study of the pretreatment performance of the application of magnetic molecularly imprinted polymer in water and oil,the other is the preparation of magnetic MOF molecularly imprinted polymer and the study of the adsorption performance of organic pollutants.The details are as follows:（1）Benzo（α）pyrene is one of the most dangerous pollutants,seriously endangering aquatic ecosystems and food（oily substances）safety.At present,magnetic molecular imprinting technology is widely used in the detection of pollutants because of its high selectivity.However,most molecularly imprinting polymers（MMIPs）can only achieve good dispersion within a single phase,which greatly limits the use of molecularly imprinted materials.A novel Benzo（α）pyrene MMIPs（BMs）was synthesized for the pretreatment of benzo（α）pyrene in environmental water and vegetable oil.The synthesized material not only has good hydrophilic property,but also has good lipophilic property after drying.The results showed that benzo pyrene molecularly imprinted magnetic clusters had strong magnetic separation ability,fast adsorption rate（5 min）,good specificity（imprinting factor=6.987）,low detection limit（0.0037μg/L in water and 0.17μg/kg in oil）,and good reuse（The recoveries of environmental water and rapeseed oil samples were 78.0%～99.0%and 81.1-111%,respectively）.BMs has a high affinity for benzo（α）pyrene and has a good application prospect in the detection and pretreatment of PAHs in complex phase samples.（2）The synthesis of magnetic molecularly imprinted polymers was guided by simulation calculation,which effectively avoided unnecessary solvent consumption in the process of screening suitable functional monomers,and shortened the preparation time.However,conventional simulation methods cannot intuit the mechanism ofπ-πstack between target molecules and functional monomers.This study introduced a new type of weak interaction visualization method,is interactive regional indicators to select suitable functional monomers,thereby preparing pyrene magnetic molecular imprinting polymers（PMs）.The results showed that PMs had good adsorption capacity（9.95 mg/g）,fast adsorption rate（5 min）,good selectivity（selectivity factorαis 5.98）,stability and reproducibility.At the same time,PMs is also applied to adsorption of pyrene and its structural analogs in tap water and vegetable oil,and the LODs（S/N=3）in water and vegetable oil samples were 0.0082-0.041μg/L and 0.53-4.0μg/kg,respectively,with high accuracy and precision.PMs has been successfully applied the pretreatment of pyrene in two substrates.（3）Magnetic functional material based on metal-organic framework（MOF）as a new type of material,low selectivity is to limit its main influencing factors in detection applications,while molecular imprinting technology can make up for this disadvantage.In this study,a magnetic zinc MOF molecular imprinting polymers（MZMMIPs）using Fe₃O₄-COOH as a magnetic carrier were prepared by a method of crystallization growth blotting cavity.By characterizing analysis and adsorption performance research,MZMMIPs not only has good magnetic separation capabilities,but also has an excellent select performance of adsorption（the selection factor is 1.6）.This means a large number of blot cavities that match target molecules in MZMMIPs.The large void channel（64 mg/g）also accelerates the adsorption rate（3 min）and elution speed（10 min）of the material,which greatly improves the preconcentration capacity of the material.The detection method in the study had been successfully applied to the determination of pyrene from vegetable oil,which has achieved excellent detection effect.The detection limit of MZMMIPs to pyrene is0.11μg/kg.The recovery was from 93.34%to 95.92%.（4）The magnetic copper MOF was prepared by one-pot method,and the optimal preparation conditions were determined by studying the mole ratio of copper ion and m-phthalic acid.After that,the structure and morphology of magnetic copper MOF molecular imprinting（MCMMIPs）were analyzed by means of scanning electron microscopy,infrared spectroscopy,XRD and vibrating sample intensity magnetometer.The results show that MCMMIPs has good magnetic response strength and can meet the requirements of magnetic separation.At the same time,the adsorption mechanism and adsorption capacity of MCMMIP were explored by studying the static adsorption,dynamic adsorption,selective adsorption and reusability of MCMMIPs in the adsorption of bisphenol A.The results show that MCMMIPs has a large adsorption capacity,and the adsorption rate and desorption rate are relatively fast,which can be well applied to the pretreatment of bisphenol A in water.