| Mesoporous MCM-41 materials reveal many good comprehensive properties:a large specific surface area and good adsorption capacity, good chemical and thermal stability, as well as certain ion exchange capacity. This work briefly describes the synthesis of the MCM-41/PVDF hybrid mesoporous silica film via hydrothermal method, and modified it as a film like test-paper by the way of physical adsorption of CN- anion receptors into three dimensional channels which material is capable of detecting CN- anion in organic solution. In addition, Thiol-functionalized MCM-41/PVDF composite mesoporous films were prepared by post-synthesized method for the application to adsorption of Pb2+ metal ions in waste water. The main results are as follows:1. Synthesis of MCM-41/PVDF hybrid mesoporous silica film:Firstly, precursor solution was prepared under certain conditions of that tetraethyl orthosilicate (TEOS) serve as silica source, the cationic surfactant cetyltrimethyl ammonium bromide (CTAB) as soft template. Mesoporous silica material MCM-41 was assembled into a three-dimensional channels on the surface of PVDF hard template by hydrothermal synthesis method, which was confirmed by the means of elemental analysis, infrared spectroscopy (IR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), nitrogen adsorption-desorption techniques and other characterization methods, the morphology and structure of organic/inorganic hybrid mesoporous silica films synthesized were characterized. The results show that:mesoporous silica material MCM-41 may be assembled in a three-dimensional pore of PVDF membrane by this method.2. Preparation of functionalized film-strips by physical adsorption of receptor:4-Br-l,8-naphthalic anhydride, as raw material, was formed into benzimidazol on the closed-loop as the fluorophore of π-extending of naphthalene ring, under certain conditions, subsequently coupled with benzene acetonitrile transform into receptors cis-3 and trans-3, where the active C-H act as recognition sites. The structure of compounds of receptor and the product were determined by]H NMR,12C NMR, ESI, IR. And the spectrum of time-response cruve and NMR titrations of isomers receptors to CN-anion was studied on the recognition properties. As a result, it was found that this isomers were not the same recognition mechanism:the mechanism of trans-3 with CN-anion was belongs to the slowly oxidation reaction, and the product in final state became its carbonyl pattern; but for the mechanism of cis-3, the pathway of reaction with CN was happened in radical reaction, then immediately, was transformed into a free state of cyanohydrin pattern of product. Moreover, trans-3 receptor was immobilized in the mesoporous channels of MCM-41/PVDF film by physical adsorption, the adsorption capacity of the mesoporous silica film to trans-3 examined by the standard curve of ultraviolet absorption spectrophotometry (UV). This kind of film-test-strip immobilized with receptor can directly generate "naked eye" effect where color change was observed from colorless to blue in conditions of different concentrations of CN-anions. The results showed that:MCM-41/PVDF composite film immobilized by trans-3 can detect 2μM CN- anion, can be used as a film strip for on-line preliminary detection to CN-in the laboratory.3. Preparation of thiol-functionalized hybrid mesoporous silica film MCM-41-SH/PVDF: MCM-41/PVDF and alkylating agent of y-mercaptopropyl-3-triethoxysilane (MPTES) were stirred under certain conditions, give the thiol-functionalized hybrid mesoporous silica film were characterized by IR emission spectra and EDS analysis of functionalized membranes. In addition, the performance of the adsorption of Pb2+ was examine by suction method and ethylene diamine tetraacetic acid (EDTA) complexometric experiments. As a result, thiol-functionalized material of SH-MCM-41 can improve the performance of adsorption of heavy metal ions PVDF membranes. |
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