Synthesis and Characterization of ZSM-5 Zeolite from Dealuminated and Fragmentated Bayat-Klaten Natural Zeolite

Abstract

Synthesis of ZSM-5 zeolite was conducted using natural zeolite of Bayat-Klaten by employing fragmentation method of sub-molten system through breaking zeolite framework into its monomer in alkaline condition at 250°C. Prior to fragmentation, one part of zeolite was treated with dealumination and the other one without dealumination, labeled as ZSM-5_a and ZSM-5_wa, respectively. Characterization with FTIR, XRD, and EDX showed that the fragmentation was successful, in which the structure of zeolite was damaged and the infrared bands due to AlO4 and SiO4 were appeared. The synthesis of ZSM-5 was performed hydrothermally using tetrapropylammonium hydroxide (TPAOH) as a directing agent of pore structure and addition of LUDOX (40% silica suspension in water). The XRD characterization showed the as synthesized materials had the structure of ZSM-5 zeolites with high crystallinity. Imaging with SEM showed the characteristic of hexagonal ZSM-5 crystals. The BET surface area analysis showed a typical surface area of microporous zeolite, 262 m2/g, and pore diameter of 1.496 nm; indicating that the ZSM-5 zeolite obtained was micropore size. The Si/Al ratio of ZSM-5_a and ZSM-5_wa were 18 and 21, respectively. These results indicated that Bayat-Klaten natural zeolite can be used as silica and alumina source for high crystalline ZSM-5 with medium Si/Al ratio and having good thermal stability. Thus, these materials are potential to be tested as fluid hydrocracking catalyst.