Comparative Study of Textural Properties for Various Silica by Nitrogen Adsorption-desorption Technique

Abstract

This work studied the textual properties of the MCM-48 and rice husk ash using nitrogen adsorption-desorption at constant low temperatures. According to the International Union of Pure and Applied Chemistry, the adsorption-desorption isotherm proved that the studied materials have a mesoporous structure with type IV. The obtained results of Langmuir, Freundlich, and Brunauer-Emmett-Teller isotherm models showed that the nitrogen adsorption followed Brunauer-Emmett-Teller isotherm. The found adsorption capacity and surface area values for MCM-48 were higher than those values for rice husk ash. Based on the Kelvin equation, Barrett, Joyner, and Halenda model was used to determine pore size distribution, pore diameter, and average pore volume for the adsorbents. The pore size distribution for MCM-48 was narrower than rice husk ash, pore diameter for MCM-48 was less than rice husk ash, and average pore volume for MCM-48 was higher than the value of average pore volume for rice hush ash. The comparison study results between the properties and those previously published for mesoporous materials indicated a convergence in the surface area of MCM-48 and pore volume. Moreover, the results of the comparison between the properties of rice husk ash showed that the surface area and pore volume were equal or less than those obtained before.