Preparation of Hydrothermally Solidified Mesoporous Materials from Diatomaceous Earth for Moisture Control Application

Abstract

Mesoporous materials were prepared by hydrothermal treatment of a powder compact consisting of natural or calcined diatomaceous earth and slaked lime. Tobermorite formed after the hydrothermal process, leading to strength improvement. The structure tangled with each tobermorite particle, causing the formation of mesopores. The bending strength and mesopore volume of the hydrothermally solidified materials derived from calcined diatomaceous earth was much higher than those derived from natural diatomaceous earth. Impurities in the natural diatomaceous earth suppressed the crystallization and growth of tobermorite, which plays an important role in strength improvement and mesopore formation. Water vapor adsorption–desorption isotherms showed that the amount of adsorbed moisture on the two kinds of hydrothermally solidified materials was almost the same.