EFFECT OF THE USE OF HEXAMETHYLENETETRAMINE COMPOUNDS FOR THE SYNTHESIS OF ZEOLITE: MORPHOLOGICAL STUDY AND FORMATION OF HIERARCHICAL PORE

• Main Author: FANNI (NIM : 20513315), YOSIA
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/24801
• Institution: Institut Teknologi Bandung

Hierarchical zeolites is a solution to the problems in the industrialized world. This zeolite can improve the diffusion of molecules, yield and selectivity of zeolite products that are not possessed by conventional zeolites (microporous zeolites). One strategy that can be done to produce hierarchical zeolite is the use mesoporogen (compounds that can direct the formation of mesoporous). Basically, the zeolite itself can be synthesized without OSDA (organic structure directing agent) and zeolite synthesis for the future will not use organic compounds at all. Hierachical zeolite has never been synthesized without the use of organic compounds. If used zeolite without OSDA, mesoporogen like micelles can not be used because there will be overlap between the formation of nucleation mesoporous silica and zeolite. Therefore, do post synthesis. In this study, which synthesized zeolite products without OSDA added by HMTA to form hierarchical pores. Hierarchical pore zeolite was synthesized using HMTA compound as an additive. Hexamethylenetetramine compounds (HMTA) has a molecular structure that is based on adamantane compounds has four N atoms bonded to three methylene. HMTA classified as a compound having low C / N ratio and the structure dimensions relative larger than zeolite so it is not suitable for use as a structure directing agent for high silica zeolites. HMTA are compounds which easily decompose depending on the reaction conditions. To see the effect of alkalinity and temperature to decomposition of HMTA, the synthesis of zeolites with various concentrations of NaOH / Si = 0.1; 0.24; 1; 5; and 7.75 is done. The synthesis is carried out using the hydrothermal method at the crystallization temperature 150ºC with a reaction time of 6 days. Zeolite product from different variation of NaOH / Si has a different frame types. One of the zeolite produced is mordenite at a concentration of NaOH / Si = 0.24. The extraction process is done to ensure organic compounds trapped inside the zeolite pores by mixing the solid zeolite with chloroform and stirred for 10 minutes, the mixture is filtered to separate the solids and filtrate. The filtrate is taken and the solvent is evaporated using a rotary evaporator, then analyzed using a nuclear magnetic resonance (NMR). From the 1H-NMR spectra obtained one peak at approximately 4.731 ppm chemical shift which is a shift of HMTA compound. The extraction process is also performed on the synthesized zeolite with a ratio of NaOH / Si = 5. The variation of the concentration of NaOH did not give effect to HMTA decomposition. Effect of temperature on the decomposition HMTA visible when the crystallization temperature increased to 175ºC at a concentration of NaOH / Si = 0.24. Zeolite synthesis was done without and with the addition of HMTA. Zeolites are synthesized without HMTA produce zeolite ZSM-5. ZSM-5 can also be produced through synthesis using HMTA. This is because HMTA decompose to compounds that direct the formation of ZSM-5. Analysis of the microstructure of all zeolite product to see differences in morphology are produced. Characterization using a scanning electron microscope (SEM) showed that the morphological changes occur in the synthesized zeolite with HMTA. The surface of the zeolite form defect and resulting an uneven surface. This proves that HMTA can change the morphology of the zeolite so it can direct the formation of hierarchical zeolite. The extraction process was repeated on the zeolite ZSM-5, peak generated in the 1H-NMR spectra is much so that it can be concluded that the compound has to decompose HMTA. Surface area analysis showed that the surface area can increase the formation of mesoporous.