| Membrane science and technology characterized by significant energy saving,clean, efficient and compatible is suitable for modem industry on energy, raw materials, reuse and eliminate the need for environmental pollution, which becomes an important part of strategies to achieve sustainable economic development.Before the mid-90s of the 20th century,mainly inorganic microporous membrane materials are zeolite and molecular sieve carbon-based. In recent years, metal-organic framework compounds, or said porous metal-organic coordination polymers or metal-organic framework compounds (MOFs) formed by the transition metal ions and the organic ligands self-assembly through complexation,unlike the former two types of material, become the third type of porous materials.Compared with the previous two types of material, the inorganic-organic hybrid polymer materials have organic and inorganic material properties,such as structural diversity, excellent performance and functional materials in selective catalysis, gas adsorption, optical and magnetic materials, which show the fascinating fields of applications and become a new decade of chemical and material science.These outstanding characteristics make MOFs material as a potential new generation of excellent membrane materials.They have potential application such as the separation of H2/CH4,O2/N2,CO2/CH4 and the separation of chiral catalysts. On the other hand, The progress of MOFs membrane is a new field of study. The preparation conditions of metal-organic frameworks (MOFs) membrane are relatively harsh and the adhesion between the material and carrier is not strong.So,the study of metal-organic framework membrane has both great challenges and great development space.In hydrothermal synthesis, we consided the different conditions to the Cu-BTC crystal synthesis such as the different C(Cu2+),C(H3BTC), reaction temperature and time.Based these reseach conditions,we tried different methods to make the Cu-BTC members grows on theα-Al2O3 support and took gas performance test. In this study, the results obtained as follows.(1)As the molar solubility of reaction solution C (Cu2+) and C (H3BTC) reduced, the crystal grain size was smaller from the 7μm to 2-3μm and the output went low.Increasing temperature could speed up the formation of crystal.However,when the temperature was higher than 120℃,it would output mixed crystal. The best synthesis temperature was at 120 ℃.The long reaction time was conducive to obtain smaller crystallite size and more perfect crystal.(2)By the in-situ hydrothermal synthesis and secondary growth method, we have studied the Cu-BTC film growth on theα-Al2O3 support. It was found that dense, continuous film could be successfully synthesized by a variable temperature methods.We have examined the suitable low and high temperature and the time distribution of the low and high temperature on the membrane synthesize.It was the best synthetic condition that the reactor synthesize temperatur was firstly at low 100℃for 24h then transfer to 120℃for 24h.The Cu-BTC membrane would be get after in-situ hydrothermal synthesis at 120℃once again.The ideal separation factor of H2/N2 was 3.71 and the flux of H2 was 1.08×10-6 mol·m-2·s-1·Pa-1.(3)Counter-diffusion hydrothermal crystallization(CDHC),which had well sovled the combination problem between MOFs materies and vector.Its operation was convenient and simple.The ideal separation factors of H2/N2,H2/CH4 and H2/CO2 were 4.67,5.76 and 8.7 separately.The flux of H2 was 4.82×10-7 mol·m-2·s-1·Pa-1(4) In Cu2+/H3BTC=1.825:1, the membrane with 3 times synthesis was the most dense by counter-diffusion hydrothermal crystallization in the microwave conditions. |
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