Distribution of nanosilica dispersions in Lecce stone

The aim of the present work is to study the application of four water-based nanosilica dispersions on carbonate rocks in terms of penetration depth, particle dimensions, physical-chemical characteristics of dispersions and stone pore radius distribution. In order to have a complete background, preliminary investigations of untreated Lecce stone and nanosilica dispersions were performed considering different parameters (e.g. porosity, viscosity, surface tension, pH, zeta potential) and TEM observations of the dispersions. Different treatments of Lecce stone were tested and studied by EDX-SEM microscopy. Silicon elemental mapping and distribution profiles were registered on samples with EDX technique. Despite the low viscosity and small dimensions of nanosilica particles, the products seemed unable to deeply penetrate in the porous substrate. However, changes in surface tension of dispersions showed an improvement of the nanodispersions transport inside the stone.