Methods and systems for treating liquids using switchable solvents

Patent metadata

Field	Value
Publication number	US-10363336-B2
Application number	US-201213480053-A
Country	US
Kind code	B2
Filing date	May 24, 2012
Priority date	Aug 26, 2011
Publication date	Jul 30, 2019
Grant date	Jul 30, 2019

Abstract

A method of treating a liquid. The method comprises providing a feed liquid comprising at least one solvent and at least one solute to a first side of a membrane. A single-phase draw solution comprising at least one of an aminium salt, an amidinium salt, and a guanidinium salt is provided to a second side of the membrane. The at least one solvent is osmosed across the membrane and into the single-phase draw solution to form a diluted single-phase draw solution. At least one of CO 2 , CS 2 , and COS is removed from the diluted single-phase draw solution to form a first multiple-phase solution comprising a first liquid phase comprising the at least one solvent, and a second liquid phase comprising at least one of an amine compound, an amidine compound, and a guanidine compound. A liquid purification system is also described.

First claim

What is claimed is:

1. A method of treating a liquid, the method comprising:
providing a feed liquid comprising at least one solvent and at least one solute to a first side of a membrane;
providing a single-phase draw solution comprising one or more of an amidinium salt, a guanidinium salt, and a tertiary aminium salt to a second side of the membrane;
drawing the at least one solvent across the membrane and into the single-phase draw solution through forward osmosis to form a diluted single-phase draw solution; and
exposing the diluted single-phase draw solution to one or more of heat, reduced pressure, and a non-reactive gas to release one or more of CO 2 , CS 2 , and COS from the diluted single-phase draw solution and form a multiple-phase solution comprising:
a first liquid phase comprising the at least one solvent; and
a second liquid phase comprising one or more of an amidine compound, a guanidine compound, and a tertiary amine compound.

2. The method of claim 1 , wherein providing the feed liquid comprises providing one or more of an aqueous saline solution, ocean water, brine, brackish water, mineralized water, industrial waste water, produced water, mining waste, food product solution, acid solution, base solution, synthetic fermentation broth, algal growth media, microbial solution, landfill leachate, radioactive material solution, and toxic material solution.

3. The method of claim 1 , further comprising:
separating the first liquid phase of the multiple-phase solution from the second liquid phase of the multiple-phase solution;
combining the separated first liquid phase with an additional amount of the at least one solvent;
exposing the combination of the separated first liquid phase and the additional amount of the at least one solvent to one or more of additional CO 2 , additional CS 2 , and additional COS to reform the single-phase draw solution; and
contacting the second side of the membrane with the reformed single-phase draw solution.

4. The method of claim 3 , further comprising adjusting an amount of one or more of the separated first liquid phase and the additional amount of the at least one solvent to impart the reformed single-phase draw solution with a greater concentration of the one or more of the tertiary aminium salt, the amidinium salt, and the guanidinium salt than a total solute concentration of the feed liquid.

5. The method of claim 3 , wherein the tertiary amine compound comprises a ratio of nitrogen to carbon of from about 1:2 to about 1:15.

6. The method of claim 5 , wherein the tertiary amine compound comprises one nitrogen atom and less than or equal to eight carbon atoms.

7. The method of claim 1 , wherein the single-phase draw solution comprises one or more of a tertiary aminium bicarbonate, a tertiary aminium carbonate, a tertiary aminium alkyl carbonate, an amidinium bicarbonate, an amidinium carbonate, an aminium alkyl carbonate, an guanidinium bicarbonate, an guanidinium carbonate, and an guanidinium alkyl carbonate.

8. The method of claim 1 , further comprising separating the first liquid phase and the second liquid phase of the multiple-phase solution to form each of a first concentrated draw solution and a liquid product, wherein the first concentrated draw solution comprises the one or more of the amidine compound, the guanidine compound, and the tertiary amine compound, and wherein the liquid product comprises the at least one solvent and a trace amount of one or more of the amidine compound, the guanidine compound, and the tertiary amine compound.

9. The method of claim 8 , wherein separating the first liquid phase and the second liquid phase of the multiple-phase solution comprises one or more of decanting, filtering, and centrifuging the multiple-phase solution.

10. The method of claim 8 , further comprising separating the at least one solvent and the trace amount of the one or more of the amidine compound, the guanidine compound, and the tertiary amine compound to form each of a purified liquid product and a second concentrated draw solution.

11. The method of claim 10 , wherein separating the at least one solvent and the trace amount of the one or more of the amidine compound, the guanidine compound, and the tertiary amine compound comprises filtering the liquid product by reverse osmosis.

12. The method of claim 10 , further comprising exposing one or more of the first concentrated draw solution and the second concentrated draw solution to one or more of additional CO 2 , additional CS 2 , additional COS, and one or more of water and alcohol to form the single-phase draw solution.

13. The method of claim 12 , further comprising separating the single-phase draw solution and at least one organic solute removed from the feed liquid.

14. A method of liquid treatment, the method comprising:
diffusing water from a feed solution through a semi-permeable membrane and into a draw solution comprising a hydrophilic solvent and one or more of water and alcohol through forward osmosis to form a diluted draw solution, the hydrophilic solvent comprising:
one or more of an amidinium cation, a guanidinium cation, and a tertiary aminium cation; and
one or more of a bicarbonate anion, a carbonate anion, and an alkyl carbonate anion;

exposing the diluted draw solution to one or more of heat, reduced pressure, and a non-reactive gas to form a first multiple-phase solution comprising a water phase and a hydrophobic solvent phase comprising a hydrophobic solvent comprising one or more of an amidine compound, a guanidinium compound, and a tertiary amine compound; and
separating the water phase and the hydrophobic solvent phase.

15. The method of claim 14 , wherein diffusing water from the feed solution through the semi-permeable membrane and into the draw solution comprises controlling a concentration of the hydrophilic solvent of the draw solution to draw the water from the feed solution by forward osmosis.

16. The method of claim 14 , further comprising delivering the water phase to a filtration device comprising a reverse osmosis membrane to remove a trace amount of one or more of the hydrophobic solvent and the hydrophilic solvent and form a purified water product.

17. The method of claim 14 , further comprising introducing CO 2 and one or more of additional water and additional alcohol to the hydrophobic solvent phase after separating the water phase and the hydrophobic solvent phase to form an additional draw solution comprising additional hydrophilic solvent and the one or more of the additional water and the additional alcohol.

18. The method of claim 14 , wherein diffusing water from the feed solution through the semi-permeable membrane and into the draw solution through forward osmosis further comprises diffusing at least one organic solute from the feed solution through the semi-permeable membrane and into the draw solution, wherein the hydrophobic solvent phase further comprises the at least one organic solute diffused from the feed solution.

19. The method of claim 18 , further comprising:
introducing CO 2 and one or more of additional water and additional alcohol to the hydrophobic solvent phase to form a second multiple-phase solution comprising an organic concentrate and an additional draw solution comprising additional hydrophilic solvent and the one or more of the additional water and the additional alcohol; and
separating the additional draw solution and the organic concentrate.

20. The method of claim 1 , wherein providing the single-phase draw solution

Assignees

• Wilson Aaron D
• Stewart Frederick F
• Stone Mark L
• Battelle Energy Alliance Llc

Inventors

• Wilson Aaron D
• Stewart Frederick F
• Stone Mark L

Classifications

• C02F2103/08

  Seawater, e.g. for desalination · CPC title

• C02F2103/06

  Contaminated groundwater or leachate · CPC title

• C02F1/445

  by forward osmosis · CPC title

• B01D61/005

  Osmotic agents; Draw solutions · CPC title

• A61L9/16 Primary

  using physical phenomena · CPC title