Fabrication of pure-phase CHA zeolite membranes with ball-milled seeds at low K+ concentration
Fabrication of pure-phase CHA zeolite membranes with ball-milled seeds at low K+ concentration
复制标题
低 K 浓度下球磨种子制备纯相 CHA 沸石膜
DOI：
10.1016/j.micromeso.2015.05.033
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发表时间：
2015-10-01
影响因子：
5.2
通讯作者：
Gu, Xuehong
中科院分区：
文献类型：
--
作者：
Jiang, Ji;Wang, Xuerui;Gu, Xuehong
采用水热二次生长法合成了CHA分子筛膜。比较了原始种子和球磨种子对CHA分子筛膜的诱导作用。从晶种尺寸、前驱体组成和晶化温度等方面对合成参数进行了广泛的研究。在单个含K+的合成介质中使用原始CHA种子(平均粒径约为3.80微米)时，膜层中容易产生杂质Mer相。在较大的SiO_2/Al_2O_3比和较低的K+浓度下，球磨晶种的诱导可以得到纯净的CHA沸石膜。与原始种子相比，合成的膜具有更好的分离性能。典型的CHA沸石膜在温度为433K，合成凝胶为11SiO_2：1Al_2O_3：1K2O：1Na2O：550H_2O的条件下，水渗透通量为2.5 kg m~(-2)h~(-1)，分离系数为2980，在348K时对90wt.%乙醇溶液的渗透汽化脱水性能较好。(C)2015 Elsevier Inc.保留所有权利。
CHA zeolite membranes were hydrothermally synthesized by secondary growth method. Original and ball-milled seeds were compared for induction of CHA zeolite membranes. The synthetic parameters were investigated extensively in terms of seed size, precursor composition and crystallization temperature. Impurity MER phase was readily generated in membrane layers when using original CHA seeds (average particle size similar to 3.80 mu m) in an individual K+-containing synthetic medium. Comparatively, pure phase CHA zeolite membranes could be obtained by induction of ball-milled seeds in a broad SiO2/Al2O3 ratio and at a low K+ concentration. The as-synthesized membranes showed better separation performance than those induced with original seeds. Typically, the CHA zeolite membrane synthesized at 433 K for 20 h in a synthesis gel of 11 SiO2:1 Al2O3:1 K2O:1 Na2O:550 H2O showed a water permeation flux of 2.5 kg m(-2) h(-1) and separation factor of 2980 for pervaporation dehydration of 90 wt.% ethanol solution at 348 K. The CHA zeolite membrane synthesized with ball-milled seeds was stable for dehydration of acidic ethanol solution (pH similar to 3) at 348 K while the membrane induced with original seeds showed a declined separation behavior. (C) 2015 Elsevier Inc. All rights reserved.