Study of the Temperature-Programmed Desorption of Carbon Dioxide (CO<sub>2</sub>) on Zeolites X Modified with Bivalent Cations

Study of physisorbed and chemisorbed carbon dioxide (CO2) species was carried out on the NaX zeolite modified by cationic exchanges with bivalent cations (Ca2+ Ba2+) temperature-programmed desorption CO2 (CO2-TPD). Others results were obtained infrared to complete study. The this research showed, in physisorption region (213 - 473 K), that increase slightly interactions molecule adsorbents and/or site. Indeed, energies reference (13.5 kJ·mol-1) are lower than exchanged zeolites E-CaX E-BaX (15.77 15.17 kJ·mol-1 respectively). In (573 873 related desorbed (bidentate carbonates: CO32-) about 81 kJ·mol-1, higher (bicarbonates: HCO32-) R-NaX (62 kJ·mol-1). addition, develops secondary adsorption sites corresponding bicarbonates 35 noted NaX.