Forward osmosis membrane and method of preparing same

A method of preparing for a forward osmosis membrane, wherein the forward osmosis membrane comprises a modified hydrophilic polyester membrane layer, the method comprising:

• (a) preparing a casting solution:
• mixing a hydrophilic polyester material, an antioxidant, and a water soluble organic solvent system together to obtain the casting solution;
• (b) coating the casting solution on a surface of a glass plate covered with a polyester mesh or directly on a clear glass plate to obtain an initial forward osmosis membrane;
• (c) treating an external layer of the initial forward osmosis membrane, and removing solvent to form a dense skin layer on the external layer to obtain a second initial forward osmosis membrane;
• (d) performing a phase separation film formation or interfacial film formation with the second initial forward osmosis membrane to obtain the forward osmosis membrane;
• wherein a hydrophilic polymer material in the casting solution is 11-13 wt. % cellulose triacetate by weight;
• the antioxidant is hindered phenolic antioxidant 2-6-Di-tert-butyl-4-methylphenol with 0.2-0.7 wt. % by weight;
• when using a 0.5 mol/L sodium chloride as a draw solution, and using a solution having ORP value of +800 mv and containing 0.01 mol/L magnesium sulfate and hydrogen peroxide as a feed solution, membrane flux and salt rejection of the forward osmosis membrane do not degrade after soaking in the feed solution for 30 days.