Fibrous Magnetic Mesoporous Silica For Preconcentration And Separation Of Environmentally Hazardous Substances

Detection of environmentally hazardous substances has always been the key focus of people’s attention and the results can make people do kinds of adjustments or take various measures. However, it’s hard to detect the hazardous substance directly for the they are at a low concentration and the sample matrix is complex. So sample pretreatment techniques are the key procedures in the preconcentration, separation and analysis of the environmentally hazardous substances, which have caused wide attention over the years by the of researchers. Magnetic Solid Phase Extraction (MSPE) is a kind of superior sample pretreatment technique which can analyse large volume environmental sample with a high enrichment efficiency in a short time. It overcomes the weakness of traditional solid phase extraction and avoids the long time package process and consuming large volume of organic solvent. The method’s efficiency depends on the magnetic materials and synthesis of different morphology, different performance of efficient magnetic solid phase extraction materials has become the focus of analytical chemistry and the important project in environmental science.This paper trends in the develop of techniques in environmentally hazardous substances analysis, different magnetic materials in MSPE (magnetic mesoporous silica, magnetic organic-inorganic hybrid mesoporous silica, magnetic carbon, magnetic polymer), main synthesis methods, property and their application in the analysis of environmental hazardous substances.Through a surfactant-templated microemulsion formation process, we synthesised fibrous monodisperse core-shell structured Fe3O4/SiO2/KCC-1nanoparticles. These nanoparticles showed fibrous monodisperse spherical morphology, high magnetism (31emu g-1), good thermal stability, large surface area (213m2g-1), direct channels, easily accessible large pores (3.7nm) and narrow size distribution. The amount of the TEOS and the surfactant were optimized in the experiment and the influence of the final morphplogy was studied. Adsorption experiments of methylene blue indicated that the material had good adsorption capacity and could perform a fast transfer of molecules (78%of equilibrium adsorption could be finished in5min), indicating its promising application in detection of environmentally hazardous substances.Phenyl-functional Fe3O4/SiO2/KCC-1was synthesised through co-condensation method. The ratio of phenyltriethoxysilane and tetraethoxysilane was optimized and its influence of the fibrous morphplogy was investigated. The morphology of the synthesised materials were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, superconducting quantum interference device, N2adsorption/desorption. The results indicated that the materials maintained the fibrous morphology, high magnetism, large surface area, easily accessible large pores which indicated its good performance in the preconcentration and detection of phthalate esters.In the study, we firstly used the phenyl-functional Fe3O4/SiO2/KCC-1in magnetic solid phase extraction to preconcentrate and separation of phthalate esters. The amount of magnetic materials, adsorption time, eluent and repeating utilization factor were optimized. The analysis of phthalate esters in environmental water samples was conducted in the optimized conditions. The results showed that the recovery could be higher than72%in10min of adsorption. The preconcentration factor was500which was fit for analysis of large-volume samples. The method owned a linear range of0.1-20ng mL-1with a correlation coefficient higher than0.999. The detection limit of phthalate eaters were between15ng L-1and57ng L-1.