Synthesis and characterization of ZSM-5 zeolite with micro- and hierarchical pore structures from Bayat natural zeolite

Abstract

Synthesis of ZSM-5 (Zeolite Socony Mobil-5) has been carried out using Bayat natural zeolite as silica and alumina source. Pretreatment on Bayat natural zeolite was performed through the process of activation, purification, dealumination, and fragmentation. The purpose of activation process is to remove the polar impurities, free oxide in the surface that cover up the pores and release the water that trapped in the pores of the crystals. The purification was conducted using Na-acetate buffer solution with ratio 1:3 (w/v). The dealumination process with 2M HCl was carried out to increase the Si/Al ratio. Fragmentation process then was carried out by using NaOH as much as 50% of NaOH was mixed with Bayat natural zeolite. Synthesis of ZSM-5 was performed using single templates method by adding TPAOH (Tetrapropylammonium hydroxide) as micropore structure directing agent. Furthermore, synthesis of hierarchical ZSM-5 using double templates method was also carried out in which PDDAM (Poly(acrylamide-co-diallyldimethylammonium chloride)) as mesoporous directing agent. The results showed xRD pattern of Microporous ZSM-5 and Hierarchical ZSM-5 had specific peaks at position 2 theta position of 7-10° and 22-25° which are the characteristics of ZSM-5 zeolite. The Si/Al molar ratio of microporous ZSM-5 and hierarchical ZSM-5 are 32.34 and 43.53.