Studies of surface chemistry — physico-chemical aspects of porous silicate surfaces

Abstract

A series of porous silicates are prepared by destabilization (precipitation) of an alkaline silicate with a polyvalent metal salt in aqueous medium. The experimental conditions are optimised in such a manner as to obtain almost all particles with precise control on their size. On an average 98 – 99% of the product is in the particle size range −300 +350 BSS mesh. For the source of silica and alumina, several starting materials of both chemical and natural sources have been used in the synthesis. The porous silicates thus developed are exhaustively characterised for bulk density, oil absorption, specific gravity, pore volume, surface area and particle size distribution. The results obtained show that the surface properties of porous silicates vary over a wide range, although the chemical composition of the products remains practically the same. It is discussed that mode of preparation, the reactants employed and the key process variables ultimately decide the surface properties and the end-use applications.