Selective membrane having a high fouling resistance and preparation method thereof

摘要

A selective membrane having a high fouling resistance. In one embodiment, the selective membrane is a composite polyamide reverse osmosis membrane in which a hydrophilic coating is applied to the polyamide layer of the membrane, the hydrophilic coating being made by covalently bonding a hydrophilic compound to residual acid chlorides of the polyamide membrane, the hydrophilic compound including (i) at least one reactive group that is adapted to covalently bond directly to the polyamide membrane, the at least one reactive group being at least one of a primary amine and a secondary amine; and (ii) at least one non-terminal hydroxyl group, wherein said hydrophilic coating provides the membrane surface with a composition of oxygen and nitrogen in a ratio of oxygen to nitrogen more than 1.6 as measured by X-ray photoelectron spectroscopy (XPS) and a contact angle of water drop on the membrane surface less than 40° as measured by goniometer.