| Metal-organic frameworks (MOFs) is a new class of hybrid organic-inorganic surpramolecular materials comprised of ordered networks formed from organic bridging ligands and inorganic metal cations. MOFs have been generated that exhibit the highest known surface areas, the lowest crystal densities as well as tunable pore size and functionality, which can be tailored for specific applications, including gas storage and separation, catalysis, drug delivery and so on. The application can be largely broadened by designing functional MOFs bearing an organic function on the organic moiety or introducing the active sites to the MOFs, which can act as hosts for a variety of guest molecules. MIL-101is one of the most typical materials of a series of MIL-n materials, and it has a maximum specific surface area of the currently reported materials. In this study, the green powder solid MIL-101is synthesized with hydrothermal method, taking Cr(NO3)3·9H2O and terephthalic acid as raw materials.Apply it to dispersion solid-phase extraction and enrichment research.(1) In this chapter, the green powder solid MIL-101was synthesized with hydrothermal method, at220℃, taking Cr(NO3)3·9H2O and terephthalic acid as raw materials. The materials were applied for the dispersion solid-phase extraction of analytes. The green powder solid MIL-101was synthesized and used for the extraction of ketopmfen, naproxen and ibuprofen from water samples for the first time. The synthesized MIL-101was characterized by X-ray diffraction, thermogravimetry, scanning electron microscope and nitrogen adsorption instrument. The MIL-101was applied as the dispersive solid phase extraction (DSPE) adsorbent for the extraction and preconcentration of ketopmfen, naproxen and ibuprofen from water samples. The extraction conditions were investigated. Under the optimized conditions, a DSPE-HPLC method for the determination of ketopmfen, naproxen and ibuprofen was developed. The method yielded a linear calibration curve in the concentration ranges from1.5to150μg L-1for the three analytes in water samples with regression coefficients (r2) of0.9981,0.9965and0.9991, respectively. The adding standard recoveries were within84.4%-113.5%. Both the intra-day and inter-day precisions (RSDs) were <10%.(2) The green powder solid MIL-101was synthesized and used for the dispersion solid-phase extraction and enrichment of2,4-dihydroxybenzophenone, benzophenone and2-hydroxy-4-methoxy-benzophenon from toner samples. Several parameters were investigated, including the amount of MIL-101, time of extraction, and the sample pH. Then using the high performance liquid chromatography (HPLC) to prove that MIL-101has an adsorption for three kinds of benzophenone sunscreens and good enrichment multiples and recovery. Good linearity was achieved in the rang of4.0μg L-1～3500μg L-1. Excellent reproducibility was found by intra-and inter-day precision which meets the request of quantitative analysis.(3) Adsorptive removal of estriol and progestin, two typical environmental endocrine (EDs), has been studied using metal-organic frameworks (MOFs) as the adsorbents for the first time. It has been studied in detail in term of kinetics, thermodynamics, adsorption isotherms, effect of pH and comparison with the adsorption of activated carbon. The adsorption kinetics and capacity of EDs generally depend on the average pore size and surface area (or pore volume) of the adsorbents. The adsorption mechanism may be explained with a simple electrostatic interaction between EDs and the adsorbent. The removal efficiency decreases in the order of MIL-101>activated carbon both in adsorption rate and adsorption capacity. Finally, it can be suggested that MOFs owning high porosity and large pore size can be applied as the potential adsorbents to remove harmful EDs in contaminated water. |
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