Fig. 4
From: Silica sol as grouting material: a physio-chemical analysis
a The Hofmeister theory where silica is a structure breaker surface and do not have a ordered hydration layer which allows structure breaker ions to adsorb closer than structure maker ions. b The theory suggested by [37] where the silica surface is a structure maker surface and thus has a ordered hydration layer which allows structure maker ions to adsorb more closely to the surface