3.1. Effect of Multi-Layers Seeds on Membrane Performance
ZSM-5 zeolite layer was synthesized on the surface of seeded tubular alumina substrates with a seed layer in three different compositions using the secondary growth method. The number and combination of each series are shown in Tables 1-3. Table 1 shows the series SLS samples prepared by a single-layer seeding method using seeds of different sizes. Table 2 shows the series DLS membranes were grown on the two-layer seeded supports using zeolite seeds of different sizes. Table 3 shows the series TLS samples were synthesized by the triple-layer seeding method using three different seed particle sizes. All the samples were subjected to an isothermal secondary growth at 180oC for 10 h and then characterized for morphology/phase-structure gas and permeance/selectivity.
Table 1: ZSM-5 tubular zeolite membranes prepared with one-layer seeding method (SLS)