Preparation of Nano pore NaX and NaY Zeolite Membranes

Nano pore Faujasite zeolite membranes were synthesized by in-situ hydrothermal method on porous ceramic tubes. Hydrothermal crystallization was carried out under an autogenously pressure and at a static condition of 100 oC. Molar composition of the starting gel of Faujasite zeolite membranes were NaX: SiO2/Al2O3=10-27, Na2O/Al2O3=4-9, H2O/Al2O3=250; NaY: SiO2/Al2O3=2.5-4, Na2O/SiO2=1.08-2, H2O/Na2O=30-200. 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 Faujasite (NaX, NaY) 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 membranes had a water flux of 2.22 and 2.67 kg/m2.h at 27 oC for NaY and NaX respectively. The best PV selectivity was obtained to be 72 and 40 for NaY and NaX respectively.

Keywords:

ceramics , nanostructures , chemical synthesis , X-ray diffraction