Comparison and Evaluation of Separation in Nanopores Zeolite Membranes

Zeolites are microporous crystalline materials with a uniform pore size distribution on a molecular scale and with high thermal and chemical stability. Zeolite membranes NaA, ZSM-5, Mordenite< NaX and NaY grown onto seeded mullite supports. Separation performance of zeolite membranes were studied for water-dimethylhydrazine mixtures using pervaporation (PV) method. The best flux and separation factor of the membranes were 0.62 kg/m2.h and 52000, respectively, for NaA zeolite membrane. Strong electrostatic interaction between ionic sites and water molecules (due to its polar nature) makes the zeolite NaA membrane very hydrophilic. Zeolite NaA membranes are thus well suited for separating liquid-phase mixtures by pervaporation method. In this study, experiments were conducted with various UDMH–water mixtures (1–20 wt. %) at 25. Total flux for UDMH–water mixtures was found to vary from 0.331 to 0.241 kg/m2.h with increasing UDMH concentration from 1 to 20 wt.%. Ionic sites of the NaA zeolite matrix play a very important role in water transport through the membrane. These sites act both as water sorption and transport sites. Surface diffusion of water occurs in an activated fashion through these sites. The precise nanoporous structure of the zeolite cage helps in a partial molecular sieving of the large solvent molecules leading to high separation factors. A comparison between experimental flux and calculated flux using Stephan Maxwell (S.M.) correlation was made and a linear trend was found to exist for water flux through the membrane with UDMH concentration.