H-Bond interactions between silicates and water during zeolite pre-nucleation

Abstract

The relative strength of water–water, water–silicate and silicate–silicate interactions are studied, in order to explain the low solubility of the monomer (Si(OH)₄), and determine the degree of dispersion of silicate clusters in solution during the hydrothermal synthesis of zeolites. We will show how the hydrogen bond interactions between water and monomeric silicate species are similar to that in pure water, whilst monomer–monomer interactions are stronger. However, when larger silicate species are also considered we find the relative hydrogen-bonding strength to follow: water–water < silicate–water < silicate–silicate. The effects of pH are also considered. The implications of the relative strength of these interactions on the formation of larger silicate species, leading to zeolite pre-nucleation, are discussed.