Modeling silica nanoparticle dissolution in TPAOH-TEOS-H₂O solutions

A model previously developed for the description of silica nanoparticle formation in the TPAOH-TEOS-H₂O system, as a preliminary step in the clear-solution synthesis of silicalite-1, is here applied to nanoparticle dissolution. The model is found to give a reasonable description of the dissolution process of as-synthesized nanoparticles. Nanoparticles heated to 70 °C have previously been observed to develop increased structural ordering, and this is incorporated into the model in a way that correlates directly with new ²⁹Si NMR data presented here. Dissolution of both as-synthesized and heated nanoparticles in alkaline solutions at different temperatures was modeled using activation energies obtained from the literature. Structural evolution occurring upon heating and dissolution of nanoparticles and/or spatial heterogeneity in nanoparticle ordering is apparent.