Energy Characteristics, Adsorption Kinetics, and Mechanism of Triethylamine Adsorption on CsZSM-۵ Zeolite

This study presents the experimental results of the main energy characteristics (ΔH, ΔG, and ΔS), thermokinetics, and the mechanism of triethylamine adsorption on CsZSM-۵ zeolite. A system consisting of a universal high-vacuum adsorption unit and a Tiana-Calvet type differential microcalorimeter DAC-۱-۱A coupled to it was used to measure the adsorption isotherm and differential heats of adsorption, providing direct quantitative and qualitative characteristics of the nature and forces of adsorption interaction between adsorbent and adsorbate. A correlation was found between the adsorption-energy characteristics, revealing the molecular mechanism of triethylamine adsorption on the surface of CsZSM-۵ zeolite. It was determined that the average molar entropy of triethylamine adsorption on CsZSM-۵ is -۵۶ J/mol·K, indicating that the mobility of triethylamine molecules on the surface of CsZSM-۵ is lower than in the liquid phase and closer to that of the solid phase, suggesting strong inhibition of triethylamine molecular mobility. It was found that the three ethyl groups of triethylamine molecules contribute to the migration of cesium cations from the zeolite framework to the zeolite surface, forming ion-molecular mechanisms with three cesium cations in the adsorbate/cation ratio of ۱N(C۲H۵)۳:۳Cs+. This work shows how calorimetric data can be used to complement crystal structure results and to detect subtle adsorbent/adsorbate interactions at the molecular level.

کلیدواژه ها:

CsZSM-۵ zeolite ، Thermokinetics ، Differential microcalorimetry ، Thermodynamics ، Adsorption mechanism ، Triethylamine