3. Choice of encapsulation method

3.1 Adsorption

Once the SMO has been synthesized, the surfactant extracted chemically or by calcination, or sometimes both, the material is impregnated with a solution containing the UV filter solubilized in a solvent (often ethanol). Depending on the volume of solution used, this is referred to as impregnation or wet impregnation (in the latter case, the volume of solution is of the order of the pore volume). To improve adsorption efficiency, successive impregnations can be carried out, the solvent being evaporated between each impregnation