T型分子筛膜的制备及异丙醇脱水应用

Preparation of T-type Zeolite Membrane and Application on Dehydration of Isopropanol

采用热浸渍–超声法在长度为800 mm的α-Al2O3陶瓷管载体上形成连续致密晶种层,在n(SiO2):n(Al2O3):n(Na2O):n(K2O):n(H2O)=1:0.055:0.23:0.08:30的溶液体系中制备了T型分子筛膜。采用扫描电子显微镜和X射线衍射仪对膜形态结构和结晶情况进行表征。将所得T型分子筛膜用于渗透汽化异丙醇脱水,考察了工作温度﹑压力以及进料初始含水率对膜脱水性能的影响,验证了T型分子筛膜的耐温、耐酸性能,监测了膜脱水过程中性能变化。结果表明:工作温度在115℃内,压力低于0.30 MPa时,所合成的T型分子筛膜具有良好的分离性能,渗透通量随温度和压力升高而增大,而渗透液含水率基本稳定;在pH为4.0 (±0.2)的酸性环境中具有良好的稳定性。

Continuous dense seed layer was formed on the α-Al2O3 ceramic tube with a length of 800 mm by hot dipping-ultrasonic method, on which T-type zeolite membranes were successfully synthesized from clear solution with the molar ration of n(SiO2):n(Al2O3):n(Na2O):n(K2O):n(H2O)=1:0.055:0.23:0.08:30. Morphology and crystallinity of T-type zeolite membranes were characterized by scanning electron microscopy and X-ray diffraction. The prepared T-type zeolite membranes were used for the dehydration of isopropanol by pervaporation in order to examine the effects of operating temperature, pressure, and initial water content on the dehydration performance of the membrane. The temperature and acid resistance of the T-type zeolite membranes were verified, and the membranes dehydration performance change was monitored. The results showed that when the operating temperature was within 115 ℃ and the pressure was lower than 0.30 MPa, the as-synthesized T-type zeolite membrane had high pervaporation performance and excellent stability in an acidic environment with a pH of 4.0(±0.2). The permeation flux increased with increasing temperature and pressure, while the permeate water content was basically stable.