Efficient Enrichment To Typical Organic Pollutants By Porous Nanomaterials In Environmental Water Samples

The separation,enrichment and determination of organic contaminants in environmental matrix have been an important branch in environmental analytical chemistry.However,up to now,especially in environmental analysis,sample pretreatment is usually the bottle-neck step due to the complex matrices of environmental samples and the extremly low concentrations of pollutants.Development of novel sorbent materials is an important approach to solve this problem.Due to their large specific surface area,open cell structure and adjustable pore volume,mesoporous cellular foams?MCFs?,metal-organic framework?MOFs?and metal-organic framework composites exhibit excellent enrichment capacity for organic pollutants.In this paper,solid-phase microextraction?SPME?and magnetic solid extraction?MSPE?based on several new porous nanomaterials were established and applied to the separation and enrichment of trace polychlorinated biphenyls,pesticides and PAHs combined with high performance liquid chromatography,the determination and analytical method of typical organic pollutants was investigated and studied in the environmental water samples.This paper is divided into four chapters:Chapter 1:the application of the new sample pretreatment techniques of SPME and MSPE in the analysis and detection of environmental pollutants is briefly introduced.The applications of mesoporous foams,metal-organic frameworks,metal-organic frameworks composite and their applications in the adsorption and separation of environmental pollutants are systematically introduced.Chapter 2:three dimensional mesoporous cellular foams?MCFs?was synthesized by template method and SPME extraction fiber was prepared by sol-gel method.Six kinds of polychlorinated biphenyls were used as the target compounds in the experiment,which were determined by combining HPLC.Orthogonal array design?OAD?was designed to optimize and explore the factors affecting the performance of SPME and compare them with commercial coatings.OAD was designed to optimize and explore the factors affecting the performance of SPME and compare them with commercial coatings.It is proved that MCFs has a three-dimensional mesoporous structure and a large surface area,which provides more active adsorption sites.It is a promising adsorption material.Chapter 3:Fe₃O₄@NH₂-MIL-101 octahedral magnetic metal organic framework composite was synthesized by simple solvent thermal reaction.The structure of Fe₃O₄@NH₂-MIL-101 was investigated by various characterization methods.Six pesticides in environmental water samples were determined by MSPE and HPLC.The results show that Fe₃O₄@NH₂-MIL-101 has a large surface area and pore volume and a strong magnetic response,which can be used as an ideal adsorbent for rapid separation and pesticide enrichment.Chapter 4:the simple hydrothermal step prepared the Co-MOF,the magnetic porous cage is obtained by pyrolysis Co-MOF composite nano materials,various characterization methods of materials have been used to analyze the structure,nine kinds of polycyclic aromatic hydrocarbons in environmental water samples were determined by HPLC,and compared with several commercial adsorption materials.Finally,kinetics and thermodynamics study proved that the CoO@C material was through the monolayer adsorption polycyclic aromatic hydrocarbons,the thermodynamic adsorption process was consistent with the Langmuir adsorption model,dynamic experimental results show that the adsorption process conforms to the secondary dynamic adsorption model.