Tuning the hydrophobicity of mesoporous silica materials for the adsorption of organic pollutant in aqueous solution

► Silylation enhances the hydrophobicity of mesoporous silica (MCM-41, HMS). ► Water capillary condensation is eliminated when silanols are sufficiently dispersed. ► Highly silylated silica exhibits Langmuir sorption isotherm for DEET in aqueous phase. ► DEET sorption capacity is 20 times higher for silylated than for parent materials.