| Nanoporous Metal-organic frameworks (MOFs) have showed their potential applications in heterogeneous catalysis, selectivity adsorption, gas separation and storage, nolinear optical material, electrical material, and magnetic material. Although many nanoporous metal-organic frameworks have been reported, studies on removing industrial pollution remain largely unexplored. In this thesis, selective adsorption and degrading catalyzed by nanoporous metal-organic frameworks was investigated, the products turned out to be environment-friendly. The kinetics method involved was also investigated in this paper.This thesis mainly composed of three parts as follows:1. We studied that MIL-53(M) (M=Al, Cr, Fe) adsorbed the methyl orange (MO) in the different solutions due to the breathing of the MIL-53(M). As the iso-structure of MIL-53(M) (M=Al, Cr,) and MIL-53(Fe), we also studied that MIL-53(M) (M=Al, Cr,) adsorbed the methyl orange (MO), and the effect of different solutions. Based on the experimental results, the adsorption mechanism for the adsorption of methyl orange was discussed, and a kinetic model was proposed. The apparent pseudo-second-order rate constants (k) with correlation constants (R) and the amount adsorbed at equilibrium (qe) of the adsorption reaction taking place on the surface of channels in the framework for each reaction have been calculated.2. Ultrasonic degradation industries dyes methyl blue (MB) catalyzed by nanoporous metal-organic frameworks [M3(BTC)2(H2O)x]n (M=CuII, CoII, NiII, BTC= benzene-1,3,5-tricarboxylate)] was studied using UV-vis spectral method. The effects of different sizes of M3(BTC)2(H2O)x, initial concentration of oxidant H2O2, the initial concentration of MB, and the power of ultrasound have been comprehensively investigated. It was found that the apparent first-order rate constant increased remarkably with the increasing of initial concentration of oxidant H2O2, the power of ultrasound. Based on the experimental results, ultrasonic degradation mechanism for the degradation MB was discussed, and a kinetic model was proposed. The apparent first-order rate constants of the catalytic reaction taking place on the surface of channels in the framework (K) for each reaction have been calculated.3. We report the photocatalytic activities of MIL-53(M) (M=Al, Cr, Fe) in photodegradation of methylene blue (MB) dye. MOFs MIL-53 is three-dimensional porous solids built up by infinite inorganic chains of corner-shared{MO4(OH, F)2}(M= Al, Cr, Fe, Ga, In, V) octahedral, cross-linked by bis-bidentate terephthalate (1,4-benzenedicarboxylate) linkers. Like TiO2 semiconductor whose conduction band was constructed by empty Ti 3d orbital, MOFs containing transition metals as structural nodes are also expected to be semiconductors since the empty d metal orbital mixed with the LUMOs of the organic linkers would formed the conduction band. Therefore, MOFs are expected to active photocatalysts, as reviewed above. Presently, MIL-53(M) is a value-added material for separating gases, including CO2, CH4, H2S and a variety of organic species. To the best of our knowledge, no attention, however, has ever been paid to study the photocatalytic properties of MIL-53(M) to date. Recently, we found that MIL-53 (Fe) exhibited photocatalytic activity for MB dye degradation under both UV-visible and visible light irradiation. The introduction of different electron acceptors in the MB aqueous solution greatly promoted the photocatalytic property of MIL-53 (Fe). To our knowledge, this synergistic enhancement in the degradation of organic pollutants by the combination of different electron acceptor and MIL-53(Fe) photocatalyst has not yet been reported. Meanwhile, the photocatalytic activities of MIL-53(A1) and MIL-53(Cr), the isostructure to MIL-53 (Fe), were also investigated to provide an insight on the correlation between metal centers of a MOFs photocatalyst and its photocatalytic activity. |
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