管壳式中空纤维膜反应器制备金属有机化合物及其CO_2吸附性能研究

Synthesis of metal organic framework with enhanced CO_2 adsorption properties using hollow fiber ultrafiltration membrane as nanoreactors

采用管壳式中空纤维膜反应器,以去离子水为溶剂,制备了ZIF-8,通过XRD、SEM、BET和CO2吸附实验研究了不同静置时间、反应物配比对ZIF-8粒子晶型、形貌、粒径、比表面积及CO2吸附性能的影响。结果表明:增加Hmim/Zn2+摩尔比有利于ZIF-8粒子的晶型完整,但比表面积则呈现先增加后降低的趋势,在n(Hmim)∶n(Zn2+)=6∶1时达到最大;延长静置时间,ZIF-8粒径逐渐增大,而比表面积与微孔体积则逐渐减小,未静置的ZIF-8粒子具有最优的CO2吸附性能,其平衡吸附量可达0.47 g/g。

A method for the synthesis of ZIF-8 by using shell and tube hollow fiber membrane as nanoreactor in DI aqueous solution is introduced. The effects of standing time and the ratios of precursors to the ZIF-8 crystal type, shape and surface area are investigated by XRD, SEM, BET and CO2 gas adsorption experiment. The results indicate that by increasing the mole ratio of Hmim/Znz ＋ , the crystal integrity of ZIF-8 is enhanced. However,the surface area of ZIF-8 is increased at first and then decreased. A maxium value of surface area is obtained when the mole ratio of Hmim/Zn2 ＋ is 6 ： 1. On the other hand, with increasing the stand time, the partical size of ZIF-8 is increased while the surface area and the microporous volume are decreased. The best CO2 gas adsorption performance of ZIF-8 is 0. 47 g/g without standing time.