Effect of synthesis parameters on performance of NaA zeolite membranes

Effects of synthesis parameters on the membrane structure and performance have been investigated for NaA zeolite membranes grown onto seeded mullite supports. Molar composition of the starting gel of NaA zeolite membranes was: SiO2/Al2O3=0.8-3.2, Na2O/Al2O3=1.6-4.6, and H2O/Al2O3=50-200. X-ray diffraction (XRD) patterns of the membranes exhibited peaks corresponding to the support and the zeolite. The crystal species were characterized by XRD and morphology of the supports subjected to crystallization was characterized by Scanning electron microscopy (SEM). Separation performance of NaA zeolite membranes was studied for water-unsymmetrical dimethylhydrazine (UDMH) mixtures using pervaporation (PV). The membranes showed good selectivity towards water in the water-UDMH mixtures. Water permeates faster because of its preferential adsorption into the nano-pores of the hydrophilic zeolite membrane. In PV of water-UDMH mixtures, the membrane exhibits a hydrophilic behavior, with a high selectivity towards water and a good flux. The best Flux and separation factor of the membranes were 0.634 kg/m2.h and 20000, respectively.

کلیدواژه ها:

NaA ، Pervaporation ، Zeolite membrane ، UDMH ، synthesis parameters