摘要
采用二次生长法在α-Al2O3载体上制备超薄型ZIF-8膜,研究了多种轻分子气体以及混合气体CO2/N2的渗透分离性能。通过SEM和XRD表征了ZIF-8晶种层的晶种涂布状态,以及ZIF-8晶体膜的生长覆盖度和晶膜厚度。研究结果表明:采用低浓度的晶种悬浮液通过浸润式连续多次涂布法,有利于获得晶种层厚度均匀且覆盖度高的超薄均匀ZIF-8晶种层,经过二次生长后所得ZIF-8膜的覆盖度高、厚度均匀且较薄,仅约为8.8?m;在所测试范围内的CO2/N2混合气体中,此ZIF-8膜对CO2具有优先选择透过性,其对CO2/N2的渗透分离因子随温度的升高而降低,随渗透压力的增加而增加,在298 K、406 kPa和CO2组分含量为50%时,该分离因子能达到6,显著超过Knudsen扩散的分离系数。
Permeation and separation properties for CO2/N2 mixtures with high quality, thin （~8.8μm） zeolitic imidazolate framework-8 （ZIF-8） membranes prepared by the secondary growth method were studied at different temperatures and feed pressures. The crystal structure, surface coverage, uniformity of the prepared ZIF-8 seeding layers and membranes were characterized by using SEM and XRD. The low concentration of the seed suspension and subsequent dip-coating method helped to obtain a more uniform, continuous and ultrathin ZIF-8 seeds layer of support; the synthesized ZIF-8 membranes offered selective permeation for CO2over N2with CO2/N2 mixture feed under the experimental conditions studied. The separation factor of CO2/N2 mixed gas through a ZIF-8 film decreased with increasing temperature, but increased with increasing feed pressure. Its separation factor of CO2＆amp;nbsp;over N2could reach 6 at 298 K, 406 kPa, and CO2 content of 50%, exceeding the Knudsen diffusion selectivity.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2014年第5期1673-1679,共7页
CIESC Journal
基金
国家重大科技专项(2013CB733506)
广西大学科研基金项目(XGZ130963)
国家自然科学基金面上项目(21276092
21376090)
亚热带建筑科学国家重点实验室自主研究课题项目(C713001z)
广西石化资源加工及过程强化技术重点实验室项目~~
