The prediction of the evolution of nanoporous materials is of great interest in various fields particularly geology, environmental sciences, and nuclear waste management. Such prediction requires the use of modeling which is generally not adapted to confined media of few nanometers. In the present study, we have characterized the evolution of hexagonal mesoporous silica having 5 nm pore size (SBA15 type) at 50°C in water and in 0.2 M XCl 2 aqueous solutions, where X are different ions (X = Mg 2+ , Ca 2+ , Fe 2+ , Ba 2+), by in-situ Small Angle X-ray Scattering. The results allowed determination of the dissolution rates of the confining media, i.e. the silica, and water diffusion through the microporous silica wall as a function of the aqueous solution composition.