Preparation Of Novel Conjugated Polymers And Their Application To Herbicides In The Environment

Herbicides are an important guarantee for high and stable agricultural production,and are essential advanced technologies in modern agriculture.Herbicides have a long half-life and high bioaccumulation,and can be residual in different environmental media through various pathways,thus posing a certain threat to the ecological environment and human health.Therefore,there is an urgent need to develop methods and analytical detection technologies for the removal of herbicides in the environment.Currently,it has been used for the adsorption and removal of pollutants in the environment.As a new type of organic adsorbent material,conjugated polymers have many advantages,such as largeπ-πsystem,stable physicochemical properties and simple synthesis.In response to the problem of traditional conjugated polymers being prone to aggregation,this paper significantly enhances the adsorption performance of conjugated polymer composites by introducing carriers and improving their porous structure,and successfully applies them to the removal and analysis of herbicides in the environment.（1）Preparation of magnetic boron nitride nanosheets modified polythiophene composites（Fe₃O₄@BNNSs@Pth）,which is used for the adsorption and removal of2,4,5-T in water.The morphology,chemical structure and physical properties of the materials were studied by scanning electron microscopy（SEM）,transmission electron microscope（TEM）,Fourier transform infrared spectroscopy（FTIR）,X-ray photoelectron spectroscopy（XPS）,X-ray diffraction（XRD）and vibrating sample magnetometer（VSM）.Studying the adsorption properties of 2,4,5-T showed that the adsorption process met pseudo-second-order kinetic and Redlich-Peterson isotherm model.The adsorption thermodynamics experiment confirmed that the adsorption process was spontaneous and endothermic.After 5 adsorption regeneration experiments,the adsorption capacity remained stable.According to the properties of adsorbent and adsorbate,FTIR and XPS analysis before and after adsorption,the adsorption mechanism mainly included hydrophobic interaction,π-πinteraction,hydrogen bond and halogen bond.The research found the maximum adsorption capacity for 2,4,5-T on Fe₃O₄@BNNSs@Pth was 377.8 mg·g^-1.The adsorbent has good adsorption performance and regeneration ability,and will not cause secondary pollution to the environment.（2）A novel ion conjugated microporous polymer（i-CMP）was prepared,and a solid-phase extraction technology based on i-CMP was established.Combined with liquid chromatography-tandem mass spectrometry（LC-MS/MS）,a detection and analysis method for triazine herbicides（desmetryn,ametryn,prometryn,trietazine,terbuthylazine,propazine and atraton）in environmental water samples was developed.The different factors affecting the extraction effect were systematically investigated.After optimization,the experimental results were obtained.The amount of material used was 15 mg,the p H of the sample solution was selected as 6,the sample flow rate was selected as 2 m L·min^-1,the sample volume was 500 m L,and the eluent was selected as 8 m L acetonitrile.The analytical method was established under optimal conditions,resulting in wide linear range(0.25-250 ng·L^-1),low detection limits(0.03-0.05 ng·L^-1),and good repeatability（within day:3.4%-9.9%;during day:4.2%-10.5%）.The method has been successfully applied to the determination of groundwater and wastewater with a spiked recovery of 77.4%-109.1%.The established analytical method has good sensitivity,accuracy,and precision,providing a new approach for the enrichment and detection of trace triazine herbicides in complex environmental matrices.