Al_(2)O_(3)中空纤维的改性及原位合成ZIF-8膜  

Modification of Alumina Hollow Fibers and In-Situ Synthesis of ZIF-8 Membranes

作　　者：尹正驰 武晓珂 杨艳伟 张华宇[1] 朱瑞敏 王正宝[1] YIN Zhengchi;WU Xiaoke;YANG Yanwei;ZHANG Huayu;ZHU Ruimin;WANG Zhengbao(College of Chemical and Biological Engineering,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]浙江大学化学工程与生物工程学院,浙江杭州310058

出　　处：《化学反应工程与工艺》2023年第1期1-10,共10页Chemical Reaction Engineering and Technology

基　　金：国家自然科学基金面上项目(21978253);中央高校基本科研业务费专项资金资助(226-2022-00020)。

摘　　要：采用化学气相沉积的方法将石墨相氮化碳(GCN)沉积到Al_(2)O_(3)中空纤维表面进行改性,在改性后的载体上通过原位晶化制备连续ZIF-8膜。采用X射线衍射(XRD)、傅里叶红外光谱(FTIR)、扫描电子显微镜(SEM)和气体透过分离测试技术,考察了GCN负载温度、负载量和前体种类以及合成液中甲酸钠添加量的影响。研究发现,向Al_(2)O_(3)载体表面负载GCN的适宜温度为350℃,温度越高,载体表面GCN的碳与氮物质的量之比(C/N比)越高,N活性位点越少,越不利于ZIF-8膜的原位晶化。在相同的负载温度下,负载时间越长,GCN对Al_(2)O_(3)载体的覆盖程度(负载量)越高,负载量过少无法形成致密膜。与三聚氰胺相比,使用尿素作为化学气相沉积的前体,在相同负载条件下GCN负载量明显下降,最终无法形成致密膜。调控合成液中甲酸钠的含量,优化的合成液配方为ZnCl_(2)、2-甲基咪唑(Hmim)、HCOONa与CH_(3)OH的物质的量之比为1:1.5:2.0:250。获得的ZIF-8膜的H_(2)透过量为6.11×10^(-7) mol/(Pa·s·m^(2)),H_(2)/N_(2)理想分离选择性为5.1。Graphitic carbon nitride(GCN)was deposited on alumina hollow fibers by chemical vapor deposition for modification,and ZIF-8 membranes were prepared by in-situ crystallization on the modified supports.The effects of GCN loading temperature,loading amount,precursor type and the amount of sodium formate in the synthesis solution were investigated by X-ray diffraction(XRD),Fourier infrared spectroscopy(FTIR),scanning electron microscopy(SEM)and gas permeation tests.It was found that the suitable temperature for loading GCN onto the alumina support surface was 350℃.The higher the temperature,the higher the C/N ratio of GCN on the support surface and the fewer N sites,which was less favorable for the in-situ crystallization of ZIF-8 membranes.At the same loading temperature,the longer the loading time,the higher the coverage(loading amount)of GCN on the alumina support.If the loading amount was too small,a dense membrane cannot be formed.Compared with melamine,using urea as the precursor for chemical vapor deposition,the loading amount decreased significantly under the same loading conditions,and finally a dense membrane could not be formed.The content of sodium formate in the synthesis solution was regulated and controlled,and the optimized formula of the synthesis solution was that the molar ratio of ZnCl_(2),Hmim(2-methylimidazole),HCOONa and CH_(3)OH was 1:1.5:2.0:250.The obtained ZIF-8 membrane showed the H_(2) permeance of 6.11×10^(-7) mol/(Pa·s·m^(2)),and the ideal separation selectivity of H_(2)/N_(2) was 5.1.

关 键 词：ZIF-8 膜 原位晶化 石墨相氮化碳 中空纤维改性 气体膜分离 

分 类 号：TQ028.2[化学工程]