原位水热合成NaY沸石膜以及在二氯乙烷与氮气混合系统的分离应用研究

Synthesis of NaY Zeolite Membrane In- suti Hydrothermally and Application in the Sparation of Dichloroethane and Nitrogen Mixture

为增大沸石膜的渗透通量，首次采用稀溶液，采用水热合成法将80mm长、孔径为3～5μm的α—Al2O3陶瓷管置于晶化釜中重复多次涂膜，合成出了无缺陷的沸石膜。XRD、SEM及气体渗透表征表明，该膜为质量盘好的NaY沸石分子筛膜。膜在焙烧去除结晶水的过程中，并未产生明显缺陷。膜时H2、N2渗透流率分别为5．95×10^-6和1．91×10^-7mol·s^-1·m^-2·Pa^-1。H2／N2、H2／C3Hx的选择因数达到3．13和12．24，超过努森扩散的值，具备了分子筛分功能。将合成的Y型沸石膜首次应用于二氯乙烷与氮气混合系统的分离。结果表明，膜两侧压差、混合气流速和浓度的变化均会带来分离因数的变化；不同阳离子交换后，沸石膜时混舍系统的分离也呈现了不同的结果。其中吸附能力较强的CaY沸石膜时混合系统的分离效果最好，分离因数为28．08，可以很好的将二氯乙烷与氯气混合气体分离。

High - penetration NaY zeolite membrane was first directly prepared hydrothermally on the outer surface of aα - Al2O3 support with poresof3-5μm. The mixture composition was Na2O2SiO2： Al2O3：H2O=17 20： 10-15： 1： 975, X-ray diffraction （XRD）, and scanning electron microscopy （SEM） indicate well cuutinuons grown 5 - 12 μm thick NaY films. The penetration of H2was up to 2.59 × 10^-6mol · s^-1 · m ^-2 · Pa^ -1 , almost one orders of magnitude higher than that of the literature. The ideal selectivity of H2/N2 and H2/C3H8 was 5.13 and 12.24 respectively. Y - type membranes were first used to separate the mixture of dichloroethanc and nitrogen as a new separation technology. The influence of pressure difference, flux , velocity and cation exchange was studied thoroughly. Membranes showed different separation abilities when being exchanged with different cations. The CaY membranes separation factor is the best one, which is up to 28.08, and the membrane can separate the mixture successfully.