ИСТИНА

Recently, porous membranes have attracted substantial attention to be used for membrane gas absorption. Existing industrial technologies lack membrane contactors able to function under elevated pressure and/or with organic liquids, because liquid absorbent penetrates into membrane pores causing pore wetting and drastic mass exchange characteristics decrease [1]. It is important that membrane resistant to liquid absorbent wetting shall have chemically modified surface as well as good transport and mechanical properties. Polysulfone (PSF) is a widely used membrane material due to its mechanical strength, thermostability, chemical stability and relative hydrophobicity. It is also an excellent material for spinning hollow fiber membranes with controlled pore sizes [2-4]. Hollow fiber membrane contactors are an attractive alternative to traditional column absorbers because they don’t have their disadvantages such as big dimensions and high capital costs. In membrane contactors, porous membrane is an interface between liquid and gas phase with contact area in membrane pores mouths. Sometimes dense gas separation membranes are used but in such case overall gas stream is not sufficient for industrial applications. It is known that membrane pore wetting causes drastic increase of membrane resistance and, therefore, mass exchange properties decrease. For a given liquid absorbent, membrane capacity to wetting depends on its properties, including membrane surface chemical properties (surface energy) and membrane structure (porosity and mean pore size). Normally, membranes having lower surface energies are less wettable than those having higher surface energies. Traditional methods of membrane surface chemical modification include surface chemical modification, plasma treatment, extra layers deposition etc. All these methods may provide increased surface hydrophilicity, but sometimes elevated hydrophilicity is not sufficient for preventing membrane wetting by organic liquids and oleophobiс modification is necessary. In this work, we prepared porous PSF hollow fiber membranes and modified their inner surface by perfluorinated acrylic copolymer (Protect Guard®) for preventing membrane wetting by liquid hydrocarbon (n-hexane) to show that such membranes can find application in gas-liquid membrane contactors.