N2-adsorption on amorphous aluminosilicates: Application of the Kelvin equation and the T-plot analysis for mixed micro-mesoporous materials
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Amorphous aluminosilicates prepared by three different sol-gel procedures were submitted to N2-adsorption for textural evaluation. For each sample series, deviation of the experimental results from the ideal pore model imposed by the Kelvin equation was investigated, providing additional information on the pore architecture and specifically, on the degree of pore connectivity. This was verified by performing a similar statistical analysis for MCM-type materials. For amorphous aluminosilicates, the pore connectivity is shown to be a function of the pH of synthesis. The different cracking behaviour during drying of silicas and aluminosilicates prepared with organic additives could also be related to the various degrees of pore connectivity. In the second part of the article, a criterion for the applicability of the T-plot analysis for mixed micro-mesoporous products was searched for. Results indicate that when the micropores cover more than 20% of the total pore volume, reliable analyses are obtained by calculating the mean intercept for a T-layer thickness going from 2 to 9 Å.
Keywordsmixed micro-mesoporous aluminosilicates Kelvin equation T-plot analysis
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