Adsorption And Photocatalytic Activities Of MIL-101 And Its Composites With Bi-containing Bimetallic Oxides/Polythiophene

Metal-organic framework (MIL-101), BiVO4 and Bi2sFeO40 were successfully synthesized by hydrothermal method. Using BiVO4 as raw material, BiVO4/MIL-101 was synthesized by hydrothermal method. Besides, using MIL-101 and Bi2sFeO40 as raw materials, Bi25FeO40/MIL-101/PTh composite was synthesized via polythiophene(PTh) Wrapping. Then the prepared samples were systematically characterized, and their adsorption and photocatalysis performance were studied. This dissertation is composed of three parts.(1) Under various conditions, the adsorption capacity of metal-organic framework, MIL-101, for cationic dyes (methylene blue (MB), rhodamine B (RB)) and anionic dyes (helianthine B (HB), acid chrome blue K (ACBK)) in aqueous solutions was measured. In particular, we have studied effects of various factors on the adsorption selectivity of MIL-101 for HB and MB in mixed solutions. The results show that the adsorption capacity to anionic dyes over MIL-101 is higher than that to cationic dyes whenever the dyes exist solely or coexist. The selection coefficient P is 5.9 at T=300K and pH=3, and it decreases gradually with the increase of pH value. In contrast, temperature has a little effect on adsorption selectivity. The mechanism for adsorption selectivity is that MIL-101 has positive surface potential, and there exists electrostatic attractive interaction between MIL-101 and anionic dye molecules while for cationic dyes, there exists repulsion interaction. Moreover, MIL-101 displays higher adsorption selectivity after modification with ethylenediamine.(2) BiVO4/MIL-101 was successfully sunthesized by hydrothermal method. The mesoporous samples were characterized by XRD, HRTEM, XPS, PL and UV-vis absorbance spectroscopy. Moreover, the photocatalytic activities of the catalysts were evaluated by measuring the degradation of rhodamine B under visible light. The result shows that the photocatalytic activities of composite were improved obviously.(3) Bi25FeO40/MIL-101/PTH composites were synthesized by in situ chemical polymerization and were characterized by XRD, HRTEM, XPS, PL and UV-vis absorbance spectroscopy. Furthermore, the photocatalytic activities of the catalysts were evaluated by measuring the degradation of rhodamine B under visible light. The result shows that, due to the rapid transferring and separation of photogenerated charge carriers through PTH connected interface between MIL-101 and Bi25Fe040, the photocatalytic activities of composites have a distinct increase.