Ethylene adsorption onto thermally treated AgA-Zeolite

• Published in: Applied surface science Vol. 542; p. 148748
• Main Authors: Monzón, J.D., Pereyra, A.M., Gonzalez, M.R., Legnoverde, M.S., Moreno, M.S., Gargiulo, N., Peluso, A., Aprea, P., Caputo, D., Basaldella, E.I.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.03.2021
• Subjects: Adsorption capacity and affinity; AgA zeolite; Ethylene; Thermal treatment; Adsorption capacity and affinity; AgA zeolite; Ethylene; Thermal treatment
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.148748

[Display omitted] •NaA was used because it allows obtaining the highest Ag+ loading by ion exchange.•Ag+ and Agm+n species improve the adsorption capacity and affinity towards ethylene.•Ag0 on zeolite A blocks active sites and inhibits 5 s1< -->π interaction.•Accessible Ag charged species improve low pressure-ethylene adsorption. Ag-Zeolite-based adsorbents were prepared in order to investigate the nature of the Ag species present in the structure and its correlation with their adsorption capacity and affinity towards ethylene. Na+ in NaA were partially replaced with Ag+ by varying the AgNO3 concentration used in the aqueous solutions, obtaining two dissimilar Ag+ exchange levels. The exchanged zeolites were treated at 90 °C for 12 h and at 350 °C for 4 h in N2 atmosphere. The X-ray diffraction (XRD), UV–visible (UV–Vis), and high-resolution transmission electron microscopy (HRTEM) analyses indicated that thermal treatment could induce framework distortion and reordering of the original Ag+ into different Ag species (Ag and Ag2O nanoparticles, nanoparticulate aggregates and Agmn+ clusters). In an overall analysis, the highest adsorption capacity and affinity towards ethylene were obtained for the samples containing mainly silver cations and reoxidizing-silver species that better promote 5 s1<->π–interaction. The increase of silver loading in heat-treated zeolite could not ensure higher olefin adsorption, due to the occurrence of non-oxidizable species. Nevertheless, at low pressure, these samples showed good affinity towards ethylene. Despite presenting inactive nanoparticles against olefin, the high content of accessible charged species remnants even after high-temperature treatment could be responsible for the improved ethylene adsorption.