Superhydrophobic/superoleophilic membranes based on covalent silanization of silica nanoparticles

To achieve highly efficient separation of oil/water mixtures, superhydrophobic/oleophilic, membranes based on covalent silanization of silica nanoparticles on metallic meshes were obtained. The membranes were prepared in a scalable two-step process. The characterization of modified nanoparticles as well as the membranes includes XPS, ATR, solid state NMR, SEM, EDS, TGA and tensile strength essays. In addition, several experiments were conducted in order to characterize the superhydrophobic behavior (water contact angle (WCA) measurements, oil flux, maximum water pressure on the membrane, affinity of the particles by organic phase, etc.). Although the silica nanoparticles are highly hydrophilic, after the modification they become strongly hydrophobic providing chemical resistance to hard water. The system allowed the separation of oil-water mixtures, being washable and reusable.