Separation Efficiency of Water/Oil Mixtures by Hydrophilic and Oleophobic Membranes Based on Stainless Steel Meshes with Openings of Various Sizes

This article is focused on development of hydrophilic and oleophobic composition which serves as a coating for substrate presented by stainless steel meshes with different sizes of their openings. Membranes obtained by dip-coating method are hydrophilic and oleophobic and this may be applied for efficient separation of organic liquids and water by simple and inexpensive gravitational separation. Investigations presented in the article show that the size of openings of meshes influence on the formation of hydrophilicity an oleophobicity of membrane, as well as the nature of used polymers, which serve as a coating, since membranes based on 400 mesh coated with Poly(diallyldimethylammonium chloride) (PDDA)/pentadecafluorooctanoic acid (PFOA)/SiO2 demonstrate different wettability in regard to organic liquids of different densities. In particular, membrane based on mesh 400 coated with PDDA/PFOA/SiO2 exhibits strong oleophobicity to less dense non-polar organic solvents - kerosene, which does not penetrate the membrane, while more dense liquids, such as vacuum pump oil, are able to penetrate it, but the rate of penetration is rather slow, 10 ml per 21 min. Obtaining of membranes with uniform coating by hydrophilic-oleophobic compositions without clogging of their openings and creation of openings of required sizes for a particular case is also a subject of study of this article.