Estudio químico-cuántico de la capacidad de adsorción de un colorante orgánico en un modelo de zeolita

Abstract

Abstract: By employing computer simulations, the present thesis examines the capacity of X-type and Y-type faujasite zeolites to adsorb methyl orange, an organic compound widely used in the dye industry. The zeolites and the adsorbate structures were modeled employing the Materials Studio software. The X-type faujasite zeolite consisted of 108 silicon atoms, 84 aluminum atoms, 84 hydrogen atoms, and 384 oxygen atoms, giving a Si/Al ratio of 1.28. Its counterpart, the structure of Y-type faujasite zeolite, contained 138 silicon atoms, 54 aluminum atoms, 54 hydrogen atoms, and 384 oxygen atoms (Si/Al ratio of 2.5). The structure of methyl orange was obtained from ChemSpider molecular database. To calculate adsorption energies, Density Functional Theory (DFT) total-energy calculations were performed using the VASP program. The computed adsorption energy for the X-type faujasite zeolite was 0.3 eV (30.87 kJ/mol) which suggests a weak interaction (physisorption). On the other hand, with a calculated value of 3.62 eV (324.52 kJ/mol), the interaction of the dye with Y-type faujasite zeolite is strong, involving chemical interactions mostly (chemisorption)