Thermoporosimetry of n-alkanes for characterization of mesoporous SBA-15 silicas – Refinement of methodology

Abstract

This report focused on setting up general experimental protocols for n-alkanes thermoporosimetry (TPM) in application for the study of porosity in a series of mesoporous SBA-15 silicas. The results were referred to the porosity characteristics obtained from nitrogen adsorption/desorption at −196 °C and quasi-equilibrated temperature programmed desorption and adsorption (QE-TPDA) of nonane. n-Hexane, n-heptane and n-octane were used as liquid probes in TPM experiments. For the first time the role of heating and cooling rate and liquid to solid mass ratio in n-alkane-TPM measurements was evaluated. n-Heptane was found to be the most appropriate n-alkane probe, n-octane admissible one, and n-hexane unsuitable due to the strong dependence of the DSC effects on choice of experimental conditions. Empirical calibration equations for n-heptane and n-octane thermoporosimetry were established.