Preparation Of Magnetic Porous Carbon Composites And Their Application In Magnetic Solid Phase Extraction

As the pollution of the water environment intensifies,the normal life of human beings is affected to varying degrees.In recent years,the trace exposure of synthetic organic compounds(such as pyrethroid pesticides,polychlorinated biphenyl compounds and brominated flame retardants,etc.)in the environmental system has attracted widespread attention from the scientific community.It has the characteristics of biological enrichment,relatively stable structure,and strong toxicity,and it is difficult to degrade in natural systems.Therefore,it is particularly important to develop simple,efficient,stable and reliable analysis and detection methods for pollution control and environmental remediation of such substances.Recently,the research on magnetic solid phase extraction(MSPE)has made considerable progress.This method has high adsorption efficiency.It is environmentally friendly,and uses relatively small amounts of organic solvents.The technology has been widely applied in the analysis of trace organics in environmental media.The main adsorption materials used in this method include carbon nanotubes,C₃N₄,graphene,and MOF.Biomass materials have a wide range of sources,low prices,stable physical and chemical properties,and large specific surface areas.These characteristics make them have a good structural foundation and show certain advantages in the application of magnetic solid phase extraction.This article intends to select sugar cane peel,mung bean,etc.as the precursors of bio-carbon materials to prepare a series of magnetic-loaded composite materials.Pyrethroid pesticides,polychlorinated biphenyl compounds and brominated flame retardants are used as target pollutants to evaluate their magnetic properties and extraction performance,and discuss the external factors that affect the properties of magnetic solid phase extraction and adsorption process.The main research contents are as follows:1?Preparation and structural characterization of magnetically loaded porous carbon compositesBased on respectively mixed calcining method,impregnation calcining method and template calcining method and using sugar cane skin,mung bean and ZIF-8 as carbon sources,magnetic sugar cane skin(CSC)carbonized material Co Fe₂O₄@CSC as well as magnetic porous carbon(MPB?CZIF-8)were prepared succefully.X-ray powder diffraction(XRD),thermogravimetric analyzer(TGA),transmission electron microscope(TEM),scanning electron microscope(SEM)and vibrating sample magnetometer(VSM)were used to characterize the structure of the prepared materials.2?Magnetic solid phase extraction of target pollutants by magnetic porous carbon compositeCommon pollutants such as pyrethroid pesticides,polychlorinated biphenyl compounds,and brominated flame retardants are selected as the research objects to discuss the influence of external factors such as material composition and usage,system p H,salinity,adsorption time,elution solvent,etc.The effect of magnetic solid phase extraction and the reusability of composite materials were measured.3?Study on the process of composite materials on the magnetic solid phase extraction of target pollutantsThrough the study of the adsorption kinetics,isotherm and thermodynamic process of the target pollutants extracted by the composite material,the mechanism of interaction between the material and the target is discussed.4?Analysis and detection of actual environmental water samplesUnder the best MSPE conditions,the prepared materials were applied to the analysis and detection of some actual environmental water samples(such as Xuanwu Lake water,Yangtze River water)and tap water to evaluate the accuracy and reliability of the established method.