Adsorption Equilibria of CO2, CH4, N2, O2, and Ar on High Silica Zeolites

Abstract

Adsorption equilibria of CO₂, CH₄, N₂, O₂, and Ar were determined on three lab-synthesized ZSM-5 adsorbents and four commercially available high silica zeolites including HiSiv-3000, HSZ-980HOA, HSZ-890HOA, and HSZ-390HUA. The synthesized ZSM-5 samples have a similar pore textural property (Brunauer–Emmett–Teller (BET) surface area and pore volume) as that of HiSiv-3000. The BET surface areas and total pore volume of the ZSM-5 sample were found to be ～300 m²·g^–1 and 0.2 cm³·g^–1, respectively. The synthesized materials have relatively higher adsorption capacities than those of HiSiv-3000 for the gases studied in this work. The order of adsorption capacities of CO₂, CH₄, N₂, Ar, and O₂ on each high silica zeolite follows the order of their polarizabilities. The selectivities of N₂/O₂ and Ar/O₂ pairs are close to 1.0, suggesting that it is very difficult to separate them by equilibrium-based adsorption processes. HSZ-890HOA and synthesized DT-100 showed higher equilibrium selectivities for CO₂ over N₂ and CH₄, implying that they are potential adsorbents for CO₂ separation from flue gases as well as landfill gases.