Perpustakaan Digital ITB

The ability of the mordenite as adsorbent of gases that caused air pollution is interested topic as well as mordenite as the protonated transfer. In this study, we would like to observe the changes of adsorb energies that occurs in one layer of protonated mordenite (H-MOR) through by ammonia (NH3) and water (H2O) molecule. The energy changes are calculating when adsorbed molecules (ammonia and water) added at the system, it lies on 7.5 A from outer atoms to reach the core of the system through 12 membered rings (move on z axis) near T4 Bronsted site of H-MOR. Then we also consider the opposite case. Next, we interested to investigate the behavior of the systems when adsorbed molecules interact with main channel of T4 Bronsted site. We use one layer of H-MOR with lattice parameter a = 18:256 A, b = 20:534Aand c = 22:542A and alpha = 90o, beta = 90o and = 90o. The value a and b are expected from International Zeolite Association (IZA) database, and we strecth the c value to put adsorbed molecule. Its contains 153 total atoms in one lattice which consist of 104 oxygen atoms, 47 silicon atoms, an aluminum atoms and a hydrogen atoms. Furthermore, as adsorbed molecule we attach NH3 or H2O molecule to the system. The base structure of H-MOR optimized by Optimization by Direct Inversion in the Iterative Subspace (ODIIS) with DFT in CPMD program package. The result shows that shape of the energy changes is like a well, with the highest energy adsorb occurred when adsorbed molecules placed at the farthest, otherwise the lowest energy occurred when NH3 placed at the center of mordenite molecule. The investigation of the behavior of Bronsted site in T4 at our system with appearance of adsorbed molecules is found that the adsorbed molecules are tend to go away from that site without kidnapping the H atom from H-MOR.