Synthesis And Performances Of Coordination Compound:Adsorption And Photocatalytic Degradation Of Typical Organic Dyes

With the deterioration of water environmental pollution, conventional water treatment technology face enormous challenges. Nowdays, the development of environmental material technology has proved several advanced methods for water environmental pollution, which infact is using novel environmental materials acting as absorbents or photocatalysts to assist the conventional water treatment technology to solve the problem of water pollution. So essentially, the research and development of new environmental materials becomes the key to the questions in the technology. Coordination compounds, a new kind of hybrid materials which is constructed by virous combinations of different metal atoms and different organic ligands, exhibit virous functions and qualities. Just recently, an increasing number of the widely use of coordination compounds in the fileds of gas srorage and sepereation, catalytic, light,electricity, magnetism and adsorption has been reported. In particular, more and more research has been made in the application of coordination compounds in adsorption and photocatalytic degradation of organic dye pollutants. In this work, several coordination compounds with different structure and adsorption or photocatalytic properties has been designed and synthesized under hydrothermal conditions following the cryatal engineering principle, and characterized by serval instruments. What's more, the adsorption and photocatalytic organic dyes experiments has been used to test the performance of these coordination compounds. And the mechanism in the experiments was studied. These results were briefly described as follows:1. A novel organic–inorganic hybrid material named?4-Hap?₄[Mo8O26]?1? was synthesized under hydrothermal conditions. Compound 1 exhibited ultra-high uptake efficiency and capacity to MB, and the adsorption process followed pseudo-second-order kinetic model as well as Langmuir isotherms. The adsorption of MB onto1 at various temperatures showed that the adsorption is spontaneous?negative?35?G??, endothermic?positive ?H?? and the randomness increases?positive ?S?? with the adsorption process. Compound 1 also preferred to uptake MB from MB/MO mixture and MB/RhB mixture, which encourage us to prepare SPE column with 1 as filler packing. Our self-made SPE column can achieve rapid and efficiently separation of MB and MO from their mixture, which also exhibit excellent stability. Further researches should be carried out to clarify the adsorptive activities on other organic pollutants.2. Four novel coordination compounds based on d¹⁰ metals, 1,10-phenanthroline?phen? and 2,2',3,3'-Oxydiphthalic acid?2,2',3,3'-odpt?/3,5-di?3,4-dicarboxylphenyloxy?benzoic acid?dcpb? / 1,3-?3',4'-carboxylphenoxy?benzene?cpb? respectively, namely [Co₂?phen?₄?2,2',3,3'-H₂odpt?₂]·14H₂O?2?, [Co₂?phen?₄?H₄dcpb?₂]·14H₂O?3?, [Cu?phen??H_dcpb?]?4?, and [Mn?phen?₂?H₂cpb?]?5?, have been synthesized under hydrothermal conditions and characterized by the methods of single crystal X-Ray diffraction, FTIR, elemental analysis and UV–vis diffuse spectrum. Isostructural compounds 2 and 3 consist discrete neutral [Co₂?phen?₄?L?₂]?L=2,2',3,3'-odpt for 2 and dcpb for 3? and lattice water molecules, forming 3D frameworks with the aid of rich hydrogen bonding interactions. Compounds 4 is built up of discrete neutral [Cu?phen??H_dcpb?] units to construct 3D framework via ? – ? stacking interactions. Compound 5 consists of 1D neutral [Mn?phen?₂?H₂cpb?] helix chains, and further forming 3D framework via rich hydrogen-bonding interactions. The photocatalytic activities of degradation of methylene blue?MB? and methyl orange?MO? in compounds 2-5 under UV light irradiation were determined, and the results revealed that compound 5 can decompose MB and MO efficiently. The different degradation efficiency of compounds 2-5 implied that the HOMO-LUMO gap should be utilized to describe the discrete character of the light-induced transitions in the coordination compounds.3. A novel 3D Zn?II?-based metal-organic framework [Zn₂?odpt??bipy??H₂O?]?bipy?_0.5?6??H₄odpt = 4,4?-oxidiphthalic acid, bipy = 4,4'-bipydine? has been hydrothermally synthesized and characterized by the Single crystal X-Ray diffraction, Fourier Transform infrared spectroscopy?FTIR?, UV – vis diffuse spectrum, and thermal gravimetric analysis?TGA?. Compound 6 shows highly efficient photocatalytic activity on the degradation of individual methylene blue?MB? and methyl orange?MO?, while exhibit a preferential photocatalytic degradation of MO in the MO/MB mixture under UV light irradiation. The possible photocatalytic mechanism was also proposed and confirmed by trapping experiments of radicals via the addition isopropanol?IPA? as radical scavenger. And compound 6 exhibit excellent recyclability and stability, which can achieve good deposition efficiency to MB for five runs.