E3S Web of Conf.
Volume 401, 2023V International Scientific Conference “Construction Mechanics, Hydraulics and Water Resources Engineering” (CONMECHYDRO - 2023)
|Number of page(s)||11|
|Section||Ecology, Hydropower Engineering and Modeling of Physical Processes|
|Published online||11 July 2023|
Basic thermodynamic characteristics and isotherm of ammonia adsorption in NaZSM-5 and LiZSM-5 zeolites
1 Tashkent University of Information Technologies named after Muhammad al-Khwarizmi, Tashkent, Uzbekistan
2 Namangan Institute of Engineering and Technology, Namangan, Uzbekistan
* Corresponding author: email@example.com
This paper presents the results of isotherm and basic (ΔH, ΔF, and ΔS) thermodynamic characteristics of ammonia adsorption in Na zeolites2,87 ZSM-5 and Li3,37 ZSM-5; also the adsorption isotherm is described by the bulk micro-pore filling theory (BFM) equations. The correlation between adsorption-energy characteristics is found, and the molecular mechanism of ammonia adsorption in Na2,87ZSM-5 and Li3,37ZSM-5 zeolites in the whole filling region is revealed. The ammonia adsorbed in NaZSM-5 and LiZSM-5 zeolites is located in the first coordination sphere with Na+ and Li+ cations, forming octa- and hexaammonia complexes. From the adsorption thermokinetics, it was determined that Li+ cations are located in the screened positions of the ZSM-5 zeolite crystal lattice. The adsorption of ammonia molecule results in Li+ cations migration from the zeolite lattice into junctions formed by the intersection of straight and zigzag channels and the formation of ion/molecular complexes of various multiplicity in them. It was determined that the average molar entropy of ammonia adsorption on NaZSM-5 and LiZSM-5 zeolites indicates that the mobility of ammonia molecules in the zeolite is below the liquid phase and close to the mobility of the solid phase, indicating a strong limitation of mobility of ammonia adsorbed on the cations.
© The Authors, published by EDP Sciences, 2023
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