在多孔α-Al_2O_3陶瓷管上合成NaY沸石分子筛膜

Preparation of zeolite NaY membrane on porous α-Al_2O_3tubes

为增大沸石膜的渗透通量,采用水热合成法将两段80mm长、孔径为3～5μm的α-Al2O3陶瓷管分别置于40cm长的晶化釜釜顶与釜底,重复多次涂膜,合成出了无缺陷的沸石膜.XRD、SEM及气体渗透表征表明,该膜确为NaY沸石分子筛膜.在釜顶合成的膜较薄,约为5μm;釜底合成的膜较厚,约为12μm.膜在焙烧去除结晶水的过程中,并未产生明显缺陷.釜顶合成的膜的渗透通量要比釜底合成的膜的渗透通量大1个数量级.在室温下,釜顶合成的膜对H2、N2渗透流率分别为7.95×10-6和2.56×10-7mol.s-1.m-2.Pa-1.H2/N2、H2/C3H8的选择因数分别达到3.13和12.24,可用于相关气体的分离.

NaY zeolite membrane was grown hydrothermally on the surface of two porous, 80 mm length α-Al_2O_3 tubes which were placed at the top and the bottom of 40 cm long reactor respectively to improve the permeance. Pore size of the support was 3~5 μm. The outer-surface of the porous support was completely covered with NaY zeolite crystals and the thickness of the membrane was about 5 μm from the top and 12 μm from the bottom, judging from the XRD, SEM and gas permeation measurement. No remarkable defects were formed through removing crystallized water. The permeance of membrane from top is one order of magnitude bigger than that from bottom. Permeance of H_2, N_2 is 7.95×10^(-6) and 2.56×10^(-7) mol·s^(-1)·m^(-2)·Pa^(-1) respectively, separation factor for H_2/N_2, H_2/C_3H_8 is 3.13 and 12.24 respectively under room temperature by using the membrane synthesized from the top of the reactor. This kind of membrane can be used to separate some relevant gases.