	US 7,445,712 B2
	Asymmetric forward osmosis membranes
Jack Herron, Corvallis, Oreg. (US)
Assigned to Hydration Technologies Inc., Albany, Oreg. (US)
Filed on Apr. 07, 2005, as Appl. No. 11/101,691.
Prior Publication US 2006/0226067 A1, Oct. 12, 2006
Int. Cl. B01D 39/00 (2006.01); B01D 39/14 (2006.01); B01D 29/46 (2006.01); B01D 71/10 (2006.01)

U.S. Cl. 210—500.29 [210/500.27; 210/490; 264/41]

14 Claims

1. An asymmetric forward osmosis membrane having three layers comprising:

(a) a skin layer made from polymeric material having a top surface as a rejection surface of the asymmetric forward osmosis membrane, and a bottom surface, wherein the density of the skin layer is greater than 50% polymer by volume, and wherein the skin layer has an average thickness of from about 8 to about 18 microns;

(b) a porous scaffold layer having a first surface bonded to the bottom surface of the skin layer and a second surface, wherein the scaffold layer is made from the same polymeric material as the skin layer and wherein the density of the scaffold layer is from about 15% to about 30% by volume, and wherein the scaffold layer has an average thickness of from about 25 to about 75 microns; and