Silver Nitrate Impregnated Pellet-Type Adsorbents for Propylene/Propane Separation

Adsorptive separation of propylene from propane using adsorption has attracted much attention due to its energy efficiency compared to distillation. We prepared propylene-selective adsorbents suitable for pressure swing adsorption (PSA) separation by impregnating AgNO3 on high-surface-area pellets such as silica, clay, and aluminosilica as substrates. Considering adsorption capacity, selectivity, desorption rate, and pellet crush strength before and after impregnation, AgNO3/aluminosilica was the most suitable adsorbent among the three adsorbents. A large portion of the AgNO3 was located inside micropores in the aluminosilica after impregnation. The propylene adsorption capacity of AgNO3/aluminosilica was 2.3 mmol/g, and the selectivity of propylene over propane was 3.1 at 298 K and 3 kgf/cm2. However, the adsorption capacity of AgNO3/aluminosilica for propylene decreased by exposing the adsorbent to hydrogen.