Studies on Different Support Seeding Conditions Applied in the Formation of NaY Zeolite Membrane

Exploring the efficient synthesis method is essential in producing zeolite membranes with minimum defects. Seeding prior hydrothermal synthesis (HT) is the major parameters that affecting the quality of zeolite membrane formed. The colloidal stability of the NaY seed solution and its attachment to the support were studied by varying the pH of the seed solutions. Three seeding methods, including dip-coating, spin coating and vacuum coating, were studied in forming NaY zeolite seed layer. Then, the seeded alumina supports were subjected to hydrothermal treatment (HT) in order to form NaY zeolite membranes. The effect of NaY seeds solution colloidal stability, electrostatic attachment between seeds and support and the seeding methods on the properties of the quality of the formed NaY zeolite membranes were investigated. The zeta potential of the seed solution was measured with respect to different pH of the seed solution. The formed NaY zeolite membrane samples were characterized with X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) and Energy dispersive X-Ray spectroscopy (EDX). Spin coating and vacuum coating displayed better seeds coverage onto the alumina support due to the vacuum lock mechanism however excessive seeds accumulation onto the alumina support will inhibit zeolite growth and expansion hence to produce NaY zeolite membranes with cracks. Nonetheless, seeded supports by dip coating method display less coverage on the support however with a proper selection pH of the seeding solution with relates to its zeta potential, stable aqueous colloidal dispersion of the seeds solution and better attachment between the zeolite seeds and the support could be achieved in order to form zeolite NaY membranes with least defects. © 2019 Elsevier Ltd.