Seeding of porous alumina substrate with MFI zeolite nanocrystals using spin-coating technique

摘要

Zeolite membranes offer a great potential for applications in many challenging separation processes. Controlled thickness of zeolite membrane allows high flux and excellent selectivity due to shape-selective properties of zeolites. Although some zeolite membranes are commercially available; producing cheap, controlled and high-throughput production of zeolite membranes still remains a challenge [1]. The controlled fabrication of zeolite membranes including synthesis time, crystal orientation and thickness under microwave heating have been reported elsewhere [2-4]. One of the approaches to control the nucleation and crystallization of MFI zeolite membrane in the secondary growth microwave-assisted hydrothermal technique is to control the seeds distribution on the surface of the support/substrate. Many methods have been explored to coat the seed crystals onto the substrate surface, including dip-coating [5], rubbing [7] and vacuum seeding [6]. Although these seeding methods improve membrane synthesis modestly, they had their own limitations. To our knowledge, no work has been reported on seeding alumina substrate with MFI zeolite seeds using spin-coating technique. In this research work, MFI zeolite seeds were synthesised by microwave-assisted hydrothermal technique and utilized for seeding the surface of a flat disk shaped alumina substrate using spin-coating seeding technique. The effect of seeding solution concentration and number of repeated spin-coating runs on the coverage of the alumina substrate surface were investigated.