Reverse osmosis membrane

• US 4,039,440 A
• Filed: 01/16/1975
• Issued: 08/02/1977
• Est. Priority Date: 09/19/1972
• Status: Expired due to Term

• Current Assignee: The United States of America as represented by the Secretary of the Interior
• Original Assignee: The United States of America as represented by the Secretary of the Interior
• Inventors: Cadotte, John E.
• Primary Examiner(s): Spear, Jr., Frank A.
• Application Number:
  US05/541,477
• Time in Patent Office: 929 Days
• Field of Search: 210/23 H, 210/321 R, 210/500 M, 264/41
• US Class Current: 210/654
• CPC Class Codes: B01D 69/125 In situ manufacturing by polymerisation, polycondensation, cross-linking or chemical reaction
• CPC Class Codes: B01D 71/601 Polyethylenimine

Abstract

A reverse osmosis membrane is prepared by reaction of a film or layer of polyethylenimine with a polyfunctional reagent whose functional groups are capable of reacting with amine groups. The polyfunctional reagent is preferably a water-soluble, aromatic or heterocyclic compound having acid chloride or isocyanate functional groups.

The membrane is preferably prepared in situ on a polysulfone or chlorinated polyvinyl chloride support by initial formation of a layer of polyethylenimine on the support, followed by interfacial reaction with the polyfunctional reagent to produce a thin surface coating possessing salt barrier characteristics.

Claims

1. A process for the preparation of a reverse osmosis membrane consisting of the steps of (1) coating a porous support with a film of polyethyleneimine;

(2) contacting the product of step (1) with a solution of a polyfunctional cross-linking reagent in a non-polar organic solvent, said cross-linking reagent consisting of isophthaloyl chloride; and

() heat curing the product of step (2) at a temperature of about 90°

to 130°

C. for a period of about 5 to 30 minutes.

2. The process of claim 1 in which said porous support comprises polysulfone.

3. The process of claim 1 in which said porous support comprises chlorinated polyvinyl chloride.

4. A reverse osmosis membrane prepared by the process of claim 1.

5. In a process for desalination of saline water by reverse osmosis comprising contacting the saline water under pressure with a reverse osmosis membrane, the improvement comprising using the membrane of claim 4 as the reverse osmosis membrane.