Basic energy characteristics and isotherm of methanol adsorption on Cu 2+ ZSM-5 zeolite

• Published in: E3S web of conferences 2023, Vol.458, p.2006
• Main Authors: Ergashev, Oybek, Bakhronov, Khayot, Kholmedov, Khamid, Ganiev, Abror, Karimov, Khasan, Khalilov, Sarvar
• Format: Article
• Language: English
• ISSN: 2267-1242; 2267-1242
• DOI: 10.1051/e3sconf/202345802006

This paper presents isotherm results and basic (Δ H , Δ F and Δ S ) thermodynamic characteristics of methanol adsorption in Cu 2+ ZSM-5 zeolite. The trinomial equation of adsorption isotherm by the bulk micropore filling theory (VMOT) is also described. A correlation between adsorption-energy characteristics was found and molecular mechanisms of methanol adsorption in Cu 2+ ZSM-5 zeolite were revealed in the whole filling region. It was determined that Cu 2+ cations are located in shielded positions of the crystal lattice of zeolite ZSM-5. Adsorption of methanol molecule leads to the migration of Cu 2+ cations from the zeolite lattice to the crossings formed by the intersection of straight and zigzag channels and to the formation of ion/molecular complexes of different multiplicity in them. It was found that small polar methanol molecules form high-energy hepta complexes with Cu 2+ cation and are located in the first coordination sphere in Cu 2+ ZSM-5 zeolite. It was determined that the average molar entropy (-65 kJ/mol) of methanol adsorption indicates that in the zeolite the mobility of methanol molecules is lower than the liquid phase and close to the mobility of the solid phase.