Physical Adsorption of Gases onto Mesoporous Silica Material SBA-15

Sean C. Forrest

Abstract

Adsorption isotherms were completed over a range of temperatures in order to study the mesoporous silica material SBA-15. The adsorbates used were methane, ethane, and nitrogen while the SBA-15 served as the adsorbent. Using these data, thermodynamic quantities for these adsorption processes were calculated. Pore-size distributions for SBA-15 were created using the Dubinin-Astakhov theory and compared to those created using the Kelvin equation. Since the Dubinin-Astakhov theory is used most often to calculate the pore sizes of microporous carbon materials, comparison to the Kelvin equation allows for the evaluation of the applicability of the theory to a micro- and mesoporous silica material. In this study, both theories returned similar pore-size distributions, which suggest the validity of using Dubinin-Astakhov theory in interpreting the data from adsorption isotherms on SBA-15.