Ethylene adsorption onto thermally treated AgA-zeolite

JORGE D. MONZÓN; ANDREA M. PEREYRA; MAXIMILIANO R. GONZÁLEZ; MARÍA S. LEGNOVERDE; MARIO S. MORENO; NICOLA GARGIULO; ANTONIO PELUSO; PAOLO APREA; DOMENICO CAPUTO; ELENA I. BASALDELLA

APPLIED SURFACE SCIENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2021 vol. 542

0169-4332

Ag-Zeolite-based adsorbents were prepared inorder to investigate the nature of the Ag species present in the structure andits 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 mi-croscopy (HRTEM) analyses indicatedthat thermal treatment could induce framework distortion and reordering of theoriginal 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 thatbetter promote 5 s1<->π interaction. The  increaseof  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.