Prediction of water adsorption isotherm on 13X zeolite in different temperatures and investigating the effect of non-framework cations using dynamic simulation

Abstract

In this article, the adsorption properties of 13X zeolite have been studied using dynamic simulation. The COMPASS force field is used to identify water adsorption isotherm on 13X zeolite. Ewald and Atom-Based group methods were used for the electrostatic and Van der Waals interactions. Li+, Na+, K+, Mg2+and Ca2+ were used as non-framework cations for compensating negative charge. Water adsorption isotherms on the 13X zeolite and different non-framework cations are calculated in the 293.15 – 373.15 K temperature range. Water Adsorption capacity on 13X zeolite for all non-framework cations decreased by increasing the temperature and reducing pressure. Freundlich model was considered for describing water adsorption on 13X zeolite. Isosteric heat of adsorption using the Freundlich model was obtained between the range 44.23 - 83.13 kJ/mol, which has good compliance with the experimental results. The results showed that water has better adsorption on 13X zeolite with Na+ as a non-framework cation compared to the other non-framework cations (Li+, K+, Mg2+and Ca2+), and this type of non-framework cation is a suitable candidate for water adsorption.