Adsorption of Propylene and Propane onto Mn+X (Mn+ = Cr3+ and/or Ni2+) Zeolites and Comparison between Binary and Ternary Exchanges

Mn+X zeolites (Mn+ = Ni2+ and/or Cr3+) were prepared and characterized by various techniques. The adsorption of propylene and propane onto these zeolites was investigated, and thermodynamic properties were discussed. The objective is to establish a comparison between the binary (introduction of Ni2+ or Cr3+ instead of Na+) and ternary (introduction of Ni2+ and Cr3+ instead of Na+) exchanges. To our knowledge, there is no work in this field, in spite of a growing interest in bimetallic zeolites. Isotherms of C3H6 and C3H8 were successfully modeled using the Toth equation. A change in KH, Henry's law slope, confirms the strong and weak characters of the interactions with propylene and propane, respectively. CrNi(39)X has an intermediary behavior between Cr(39)X and Ni(40)X. It manifests specific interaction with C3H6 molecules through the deep implication of Cr3+ cations, at low coverage. With increasing adsorbate concentration, the contribution of Ni2+ occurs.