A water permeable composite membrane is disclosed herein, comprising a thin film layer on a porous substrate. The thin film comprises a polymer and amine - containing compound associated with the polymer, and the amine-containing compound comprises at least one aliphatic hydrocarbon moiety attached to an amine group. Further disclosed herein are a process for preparing the aforementioned composite membrane described herein, a reverse osmosis apparatus comprising said composite membrane, and a method utilizing said composite membrane for treating water.