清液体系高性能T型分子筛膜的制备及表征

Preparation and Characterization of High Performance Zeolite T Membranes from Clear Solutions

采用二次生长法,在廉价大孔α-Al_2O_3管状载体上通过变温热浸渍涂晶法获得连续致密的晶种层,在摩尔配比为1Si O2:0.05Al_2O_3:0.26Na2O:0.09K2O:30H2O清液体系中120℃水热晶化16 h成功制备出T型分子筛膜。实验考察了小晶种液浓度,晶化时间对T型沸石分子筛膜的形貌和性能的影响。XRD和SEM结果表明,晶化过程中晶种的外延生长和新的晶核成核过程同时进行,晶种的外延生长和新核的诱导作用产生协同作用,缩短T型沸石膜的生长时间。将制备的T型沸石分子筛膜用于75℃渗透汽化分离10wt%水/异丙醇体系,其渗透通量和分离系数分别达到2.96 kg/(m2·h)和6400。

T-type zeolite membrances with high permeation performance were successfully synthesized on the low cost macroporous α-Al2O3 tubular support by secondary growth from clear solutions. The effects of the con- centration of seeds and the membrane crystallization time on the morphology and pervaporation properties of zeo- lite T membrances. When the molar ration of the synthesis solution was 1SiO2：0.05Al2Oa：0.26Na20：0.09K20： 30H20, a high quality T zeolite membrane was obtained at crystallization temperature of 120 ℃ for 16 h, with water flux of 2.96 kg/（mLh） and separation factor of 6400 for dehydration of IPA aqueous solution by pervaporation at 75℃. XRD pattern and SEM observation suggested that the shortened membrane crystallization time resulted from the secondary nucleation induced by the seeds and the seeds epitaxial growth.