Sr2+–SAPO-34 Prepared via Coupled Partial Detemplation and Solid State Ion Exchange: Effect on Textural Properties and Carbon Dioxide Adsorption

Abstract

Sr2+–SAPO-34 materials were prepared via solid-state ion exchange (SSIE) to improve their CO2 adsorptive properties, particularly at low partial pressure, and study the effect of the ion exchange treatments on the structural and textural properties of the materials. In the past, these materials have been prepared with traditional liquid-state ion exchange (LSIE) methods yielding a strontium(II) content of about one cation per unit cell, well below the theoretical maximum and probably due to aqueous phase equilibrium constraints. Characterization of the SSIE materials included coupled thermal gravimetric analyses/Fourier transform infrared spectroscopy (TGA/FT-IR), X-ray diffraction (XRD), energy-dispersive analysis by X-rays (EDAX), surface area, and pure component CO2 equilibrium adsorption. Coupled TGA/FT-IR studies were used for the selection of the SSIE temperature for both NH4+–SAPO-34 and as-synthesized Na+–SAPO-34 starting materials. In general, the results indicated that temperatures well above th...