金属有机骨架MIL-96膜的制备和表征

Preparation and characterization of metal-organic framework MIL-96 membrane

采用反应晶种法在片式多孔α-Al2O3支撑体表面制备金属有机骨架MIL-96膜。采用X线衍射仪(XRD)和扫描电子显微镜(SEM)对MIL-96膜进行相结构和形貌表征,并考察膜的热稳定性和化学稳定性。在不同的操作温度下,对MIL-96膜的单组分气体H2、CH4、N2和CO2的渗透行为进行详细研究。结果表明:随着操作温度的升高,气体的渗透性呈现出微弱的先下降后上升的趋势,在130℃时渗透性最小,这主要源于MIL-96骨架的柔性。温度升高导致分子热运动加剧,不利于气体渗透;但当温度高于130℃时,MIL-96的柔性骨架受温度影响引起晶格震动,膜的有效孔径增加,从而气体渗透性增加。同时,H2与CH4、H2与N2、H2与CO2的理想选择性都稍有增加。

Continuous metal-organic framework MIL-96 membrane was prepared on the disk-shaped porous ct-A12 03 support via reactive seeding method. The crystal phase and the microstructure of synthesized membrane were characterized by X-ray diffractometry （XRD） and scanning electron microscopy （SEM）. Single gas permeation experiments of H2, CH4, N2 and CO2 showed that the gas permeances firstly decreased and then increased with increasing operating temperature and the lowest values occurred at 130℃, because of the flexible framework of MIL-96. The increasing operating temperature was unfavorable to gas permeation owing to the intense thermal motion of gas molecules. However, the framework of MIL-96 was flexible and the lattice vibrations would increase the effective pore size of membrane when the operating temperature exceeded 130 ℃, resulting in the increase in gas permeances. Meanwhile, the selectivity of H2 and CH4, N2 and H2, H2 and CO2 derived from single gas permeance increased.