微波场中NaA分子筛膜合成规律的研究

Synthesis Regularity of NaA Zeolite Membrane in Microwave Field

采用微波加热技术,常压回流条件下,在多孔氧化铝载体上制备出连续NaA分子筛膜,详细考察了放置方式、碱度、钠离子浓度以及合成次数对膜形成的影响.XRD和SEM表征结果显示,竖立放置和平置在顶部有利于提高膜的连续程度;高的碱度和高的钠离子浓度都不利于形成连续膜,反而溶解膜层;凝胶体系更易抑制转晶;在较短的合成时间里,多次合成有利于形成连续致密膜.

Zeolite membrane has the potential advantages in a number of applications such as separation and catalysis, chemical sensors, electrode, acoustic wave devices and optics devices. The paper reports a novel method for continuous NaA zeolite membrane deposited on porous aluminum substrate by microwave heating at ambient pressure and under reflux. The effects of placement manners, alkalinity, Na+ concentration and synthesis times on zeolite membrane formation were investigated. XRD and SEM results show that high alkalinity and high Na+ concentration don't benefit to form continuous membrane, whereas dissolve membrane layer. Among three placement manners, vertical placement and horizontal placement manners show better effects on zeolite membrane formation. In order to improve membrane quality, employing multi-stage synthesis is necessarily, which is prone to restrain transformation of NaA zeolite and increases intergrown degree of membrane in gel reactant system for short synthesis time.