Effect of drying technique on the morphological and textural characteristics of mesoporous silica synthesized in the microreactor

Abstract

The mesoporous silica with high monodisperse inter-particle voids was obtained through different drying methods (oven, freeze, and spray) of wet-gel silica. And the wet-gel silica was prepared in the microreactor system through the precipitation of TEOS. The effects of different drying techniques on the textural properties and morphology of mesoporous silica synthesized in the microreactor were studied. The textural properties of silica were evaluated using nitrogen adsorption/desorption experiments. The morphology of the silica was described using transmission electron microscopy and field-emission scanning electron microscope. It was found that the oven drying (OD) silica exhibited the most uniform pore structures and compact structures. The freeze drying silica maintained the original network of wet-cake silica after drying. Due to the rapid and uniform heating of silica in the spray drying (SD) process, the silica obtained had the more porous structure than that of OD technique. Additionally, the surface tension of solution in the SD process affected the structures of final products. And the ethanol resulted in the more porous structures of silica than that of water.