Investigation For Separation/Enrichment And Mechanism Of Pyrethroid Pesticides By Molecularly Imprinted Polymers Based On Magnetite Yeast Composites

Environmental hormones also known as endocrine compound, are synthetic exogenouschemical substances released into environment because of production and living activities andcan disrupt biological endocrine system. Environmental hormones are divided into inorganicenvironmental hormones and organic environmental hormones. Pyrethroid pesticides （PPs）have been listed in the environmental hormone, which have strong lipotropism, more stableproperties, significant bioeffects due to enrichment in biological organisms, leading toenvironmental pollution and food safety problems. Therefore, measures must be taken todetect trace PPs. Owing to characteristics of target substances and restriction of selectivity, itis necessary to separate/enrich PPs.Solid phase extraction （SPE） works as a commonly used technique to pretreat tracepollutant-contaminated wastewater, on account of its simple operation, short pretreatmenttime, easy to combine with instrument and decrease secondary pollution of organic solvent.This study adopts surface molecular imprinting technique to synthetize magnetite yeastpolymers based on traditional solid-phase extraction, selectively adsorpting PPs.This work mainly includes the following three aspects:（1） Preparation of magnetic yeastcomposites （M@Y）. Fe₃O₄/yeast composites were syntheticed by co-precipitation method,using ferric chloride （FeCl3·6H2O） and iron chloride tetrahydrate （FeCl2·4H2O）.（2）Preparation of PPs imprinted magnetite yeast polymers （MMIPs）. The study utilizes themethod of suspension polymerization to synthetize surface molecularly imprinted polymers（MMIPs） based on magnetite yeast composites. MMIPs were characterized by scanningelectron microscopy （SEM）, X-ray diffraction （XRD）, vibrating sample magnetometer （VSM）,Fourier transform infrared （FT-IR） analysis, thermogravimetric analysis （TGA）, and elementalanalysis. At the same time, the author synthesises non-molecular imprinted polymer （MNIPs）without PPs as comparision.（3） Research extraction behavior of surface molecularlyimprinted polymers （MMIPs）. The static adsorption results indicated that MMIPs have higheradsorption capacity, faster adsorption kinetics performance and prominent recognition abilityon PPs.MMIPs synthesized by the research exhibited excellent physical and chemical properties. The morphology of MMIPs was approximately spherical with the diameters ranging from3.5μm to4.3μm. The saturation magnetization （Ms） values obtained at room temperature were17.87emu/g for MMIPs. The weight loss of MMIPs around100℃was only4.17%. Accordingto the results,4.32%of the template PPswas remained on the packing after washing of theMMIPs and the adsorption capacity of MMIPs was39.64mg/g at298K.