Hydrothermal synthesis of mesoporous materials from diatomaceous earth

Abstract

AbstractHydrothermal synthesis of mesoporous materials from diatomaceous earth has been carried out under saturated steam pressure (0.2–1.56 MPa) at 393–473 K for up to 72 h by slaked lime introduction. During the hydrothermal synthesis process, calcium silicate hydrate (CSH) was among the first phase formed and invariably appeared before tobermorite. The CSH formation seemed to exert a positive effect on the strength development and pore size evolution initially; whilst the tobermorite formation appeared to further enhance the strength and narrow the pore size. With curing at 473 K for 18 h, both of the strength and pore size distribution tended to reach optimal at which the pore size distribution also ranges between mesoporous area (2–50 nm in diameter). The highest strength seemed to coincide with the finest pore size distribution of the synthesized porous material during hydrothermal processing in this study. © 2007 American Institute of Chemical Engineers AIChE J, 2007