Study Of Magnetic Titanium Oxide And Mixed Micelle System In Separation And Analysis Of Pollutant In Water

Solid phase extraction (SPE) was one of the most widely used enrichment and purification methods in the field of environmental water sample pretreatment. However, a necessary column passing process is time-consuming in traditional SPE mode, especially in analysis of large volume environmental water samples. With the development of magnetic materials, the study focused on magnetic materials used in analytical chemistry has been growing up. Based on the integration of magnetic materials and SPE technology, a novel magnetic adsorbent emerged in require instead of nonmagnetic adsorbents in traditional SPE modes, which not only retained the unique magnetic response character of magnetic materials but also not lost the adsorptive properties. Thus magnetic adsorbents can be easily separated from matrix in external magnetic field in short time, which simplified operation procedure and facilitated analysis efficiency, especially water samples of large volume.The application of magnetic solid phase extraction technology on enrichment and determination of trace pollutant in environmental water samples based on magnetic titanium nanoparticles was studied in this paper, and the main contents were as follows:(1) Magnetic Fe3O4nanoparticles were synthesized in co-precipitation method, with TiCl4and which magnetic titanium nanoparticles (Fe3O4@TiO2NPs) were also synthesized in co-precipitation method. The synthesized Fe3O4and Fe3O4@TiO2NPs were characterized. After annealed, Fe3O4@TiO2NPs were used as adsorbent to enrich pyrethroid pesticides in water samples. Afterwards the magnetic adsorbents were separated from matrix in magnetic field, and eluted with elution solvent, and then the analytes was determined by HPLC. The following extraction conditions were optimized:the ratio of Fe3O4and TiO2, the mass of Fe3O4@TiO2, extraction time, pH, ion concentration, washing condition and desorption condition.(2) Fe3O4@TiO2NPs were synthesized in hydrothermal method with TiCl4and Fe3O4NPs which were synthesized as same method as (1). The synthesized Fe3O4@TiO2NPs were characterized. In neutral condition, titanium-magnetic mixed hemimicelle was formed by Fe3O4@TiO2NPs and CTAB, which were used in adsorption of organophosphorus pesticides in environmental water samples. Then the magnetic adsorbents were separated from matrix in magnetic field, and eluted with elution solvent, and then the analytes was determined by HPLC. The following extraction conditions were optimized:the mass of CTAB, extraction time, washing condition, pH, maximal extraction volume and reuse of the sorbent.(3) Fe3O4@TiO2NPs were synthesized in co-precipitation method with TBT and Fe3O4NPs which were synthesized as same method as (1). Fe3O4@TiO2NPs were characterized. In acidic condition, magnetic mixed hemimicelle was formed by Fe3O4@TiO2NPs and SDS, which were used in adsorption of Sudan dyes in environmental water samples. Then the magnetic adsorbents were separated from matrix in magnetic field, and eluted with elution solvent, and then the analytes was determined by HPLC. The following extraction conditions were optimized:the mass of SDS, extraction time, elution condition, pH, maximal extraction volume and effect of humic acid.The common points of the three experiments above were that the advantages of magnetic materials and SPE were combined, which not only applied the unique magnetic response character of magnetic materials but utilized the adsorptive properties. In the experiment procedure, enrichment and purification were incorporated together and the time-consuming column passing process in traditional SPE mode was avoided, which facilitated analytical efficiency.