Influence on textural values of nanoporous materials by using different gases at 77 K

DEICY BARRERA; JHONNY VILLARROEL-ROCHA; KARIM SAPAG

Ottawa

Simposio; 8th International Symposium on NANOPOROUS MATERIALS (NANO-8); 2017

Universidad de Ottawa

In several applications the efficiency and selectivity of porous materials in a given process (adsorption or heterogeneous catalysis) has a direct relationship with its textural properties. This dependence has been shown and studied for different applications, such as the adsorption of gases, vapors, organic compounds, dyes, proteins, and various catalytic applications, among others. For this reason, the textural properties of the porous materials are some of the most important characteristics to be evaluated, within which are the specific surface, the porosity and the distribution of pore size. The most widely used experimental technique to determine textural properties of porous materials is the gas adsorption, where the most used adsorptive is N2 at 77 K. However, researchers argue that the quadrupole moment of the N2 molecule exhibits specific interactions with the surface silanol groups present in silica materials (like ordered mesoporous materials silica, OMMS), generating a preferential orientation effect on the N2 molecule adsorbed. In this sense, in addition to N2 adsorption at 77 K, the study of the adsorption of other vapors or gases would be useful to complement the information of the texture and/or structure of the OMMS. In this work, the N2, Ar, O2, CH4 and H2 at 77 K adsorption on MCM-41, MCM-48, SBA-15 and SBA-16 are presented where several methods/models macroscopic (DR, aS-plot, Gurvich rule, BJH and VBS) or microscopic (NLDFT and GCMC) were used, in order to complete the information about their texture and pore structure.