Patent ID: 8021553

Claim:
A process for purification of a feed solution characterized by a concentration of impurities dissolved in a solvent, the process comprising: at a first temperature, exposing the feed solution to one side of a semi-permeable membrane; directing a draw solution to an opposite side of the membrane, the draw solution comprising an organic solute, the organic solute comprising a hydrophobic component and a hydrophilic component; where an initial concentration of the organic solute in the draw solution is at least three times the concentration of impurities in the feed solution to be purified so that an osmotic pressure differential exists between the feed solution and the draw solution, the osmotic pressure differential inducing forward osmosis across the membrane, drawing solvent from the feed solution across the membrane to provide a diluted draw solution while increasing the concentration of impurities in the feed solution, wherein the diluted draw solution has a cloud point temperature above the first temperature; and following forward osmosis, heating the diluted draw solution to just above the cloud point temperature, thereby triggering precipitation of the organic solute.