Synthesis Of MOF Material And Its Application In Analysis And Detection

With the continuous development of modern agriculture,the use of pesticides,veterinary drugs and other chemicals is inevitable,so the environmental problems caused by these organic chemical residues are becoming increasingly prominent.Their high toxicity,hard degradation and accumulation in the organism help the residual organic pollutants in the environment eventually enter the human body through the food chain,thus posing a threat to human health.Therefore,the detection of these organic pollutants becomes a task of great importance.One of the key steps of detection is to develop highly efficient and selective adsorbents.Due to their excellent specific surface area,high porosity,significant thermal and chemical stability,and designable and adjustable structures,MOFs have been widely used in sample pretreatment and have become a kind of material with great potential.In this paper,several functional composites with large specific surface area and good adsorbability were synthesized under the framework of metal-organic framework,and were used in combination with chromatography to extract and analyze organic pollutants in water environment.（1）The zeolite imidazolate skeleton material ZIF-8 was synthesized by solvothermal method.As the solid phase extraction adsorbent,four organophosphorus pesticides were adsorbed and analyzed by gas chromatograph in water environment.The morphology and structure of ZIF-8 were characterized by scanning electron microscopy（SEM）and Fourier transform infrared spectroscopy（FT-IR）,then the amount of adsorbent,elution solvent and elution solvent in the pre-treatment experiment were investigated.Under the optimal experimental conditions,the four organophosphorus pesticides in the environmental water samples in a wide range（0.2 mg/L-1.2 mg/L）showed a good linear relationship（R²≥0.9916）.In the actual sample detection,the material has a good adsorption effect on the four organophosphorus pesticides,the recovery of target substances was in the range of 88.6%-104.6%,and the RSD value was less than 8.0%.（2）ZIF-8 was functionalized by chemical co-precipitation method and physical coating method,and ZIF-8@DES composite material was prepared to extract organophosphorus pesticides,and then analyzed by gas chromatography.The morphology and structure of ZIF-8@DES were characterized by SEM,XRD and FT-IR.The analysis of experimental results showed that in the range of 0.2 mg/L-1.2 mg/L,three organophosphorus pesticides showed a good linear relationship（R²:0.9880-0.9992）.In the actual sample detection,ZIF-8@DES has a good adsorption effect on three organophosphorus pesticides,the recovery was in the range of 86.3%-109.9%,and the RSD value was less than 8.0%.（3）Magnetic Fe₃O₄ particles were prepared and combined with MOF-5 materials to prepare Fe₃O₄@MOF-5 magnetic composite material,which was used as adsorbent to detect tetracycline residues in the lake water with high performance liquid chromatography.The results showed that in the linear range of tetracycline is 0.2 mg/L-2.0mg/L,the linear relationship of tetracycline was good（R²:0.9787-0.9955）.In the actual sample test,the adsorption rate of tetracycline by Fe₃O₄@MOF-5 magnetic composite material was more than 86%,and the recovery was 94.0%-105.7%.