Patent ID: 9039899
Filing Date: 2015-05-26
Classification: B01D,C02F,Y02W

Abstract:
1. A method of maximizing draw solute recovery in an osmotically driven membrane system, the method comprising the steps of: providing a first osmotically driven membrane system comprising a forward osmosis membrane, the system configured for receiving a first solution comprising a solvent on a first side of the membrane and a concentrated draw solution on a second side of the membrane; osmotically separating the solvent from the first solution with the concentrated draw solution via an osmotic concentration gradient across the membrane, thereby forming a second solution on the first side of the membrane and a dilute draw solution on the second side of the membrane, wherein the second solution comprises at least one first ionic species of solute via reverse ion exchange through the membrane; recovering at least one draw solute and the solvent from the dilute draw solution, wherein the recovered solvent comprises at least one second ionic species of solute; recycling the recovered at least one draw solute to the first osmotically driven membrane system; providing a second osmotically driven membrane system comprising a reverse osmosis membrane; pressurizing the recovered solvent in the second osmotically driven membrane system to recover a substantially pure solvent and a concentrated solution comprising the at least one second ionic species of solute; recycling the concentrated solution comprising the at least one second ionic species of solute to the first osmotically driven membrane system, wherein the concentrated solution is added to the first solution, thereby resulting in the second solution comprising the at least one first ionic species of solute and the at least one second ionic species of solute; ionically balancing the at least one first species of solute with the at least one second species of solute to form additional removable draw solutes; and recovering the additional draw solutes and a third solution from the second solution.