Forward osmosis composite membranes for concentration of lithium containing solutions

Patent metadata

Field	Value
Publication number	US-2020047124-A1
Application number	US-201916535585-A
Country	US
Kind code	A1
Filing date	Aug 8, 2019
Priority date	Aug 9, 2018
Publication date	Feb 13, 2020
Grant date	—

Abstract

A method of concentrating a lithium-containing aqueous solution, the method comprising: (i) providing a water-permeable structure having an inner surface and outer surface, wherein at least said outer surface is coated with a water-permeable hydrophilic polymer having a thermal stability of at least 100° C.; and (ii) flowing a lithium-containing aqueous feed solution having an initial concentration of lithium over said inner surface while said outer surface is in contact with an aqueous draw solution containing a higher overall ion concentration than said lithium-containing aqueous feed solution, to result in forward osmosis of water from said lithium-containing aqueous feed solution to said aqueous draw solution, and wherein said forward osmosis results in a lithium-containing aqueous product solution having an increased concentration of lithium relative to the initial concentration of lithium in the lithium-containing aqueous feed solution.

First claim

What is claimed is:

1 . A method of concentrating a lithium-containing aqueous solution, the method comprising:
providing a water-permeable structure having an inner surface and outer surface, wherein at least said outer surface is coated with a water-permeable hydrophilic polymer having a thermal stability of at least 100° C.; and flowing a lithium-containing aqueous feed solution having an initial concentration of lithium over said inner surface while said outer surface is in contact with an aqueous draw solution containing a higher overall ion concentration than said lithium-containing aqueous feed solution, to result in forward osmosis of water from said lithium-containing aqueous feed solution to said aqueous draw solution, and wherein said forward osmosis results in a lithium-containing aqueous product solution having an increased concentration of lithium relative to the initial concentration of lithium in the lithium-containing aqueous feed solution.

2 . The method of claim 1 , wherein said hydrophilic polymer comprises a fluoropolymer, polyether ether ketone (PEEK), polysulfone (PSU), poly(ethersulfone) (PES), polyetherimide (PEI), poly(phenylene sulfide) (PPS), or polybenzimidazole (PBI).

3 . The method of claim 1 , wherein said hydrophilic polymer comprises a fluoropolymer.

4 . The method of claim 3 , wherein said fluoropolymer is selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), perfluorocycloalkenes (PFCAs), perfluoroalkoxy alkanes (PFAs).

5 . The method of claim 1 , wherein said hydrophilic polymer is a hydrophilized version of polyvinylidene fluoride (PVDF).

6 . The method of claim 1 , wherein said hydrophilic polymer is coated on only the outer surface.

7 . The method of claim 1 , wherein said hydrophilic polymer is coated on both the inner and outer surfaces.

8 . The method of claim 1 , wherein said lithium-containing aqueous feed solution is provided by a selective lithium extraction process, and the lithium-containing aqueous feed solution contains lithium in a predominant amount relative to other metal species.

9 . The method of claim 8 , wherein said lithium-containing aqueous feed solution as provided by said selective lithium extraction process has an initial concentration of lithium of up to 20 g/L.

10 . The method of claim 1 , wherein said lithium-containing aqueous product solution has a concentration of lithium of at least 50 g/L.

11 . The method of claim 1 , wherein said lithium-containing aqueous product solution has a concentration of lithium of at least 100 g/L.

12 . The method of claim 1 , wherein said aqueous draw solution has an overall ion concentration of at least 200 g/L with an osmotic pressure of more than 200 bar.

13 . The method of claim 12 , wherein said aqueous draw solution is a naturally occurring geothermal brine solution.

14 . The method of claim 13 , wherein said geothermal brine solution is a spent geothermal brine solution that is depleted in lithium.

15 . The method of claim 1 , wherein said increased concentration of lithium in the lithium-containing aqueous product solution is at least 100% greater in concentration than the initial concentration of lithium in the lithium-containing aqueous feed solution.

16 . The method of claim 1 , wherein said water-permeable structure has a tubular shape.

17 . The method of claim 1 , wherein said water-permeable structure is microporous or mesoporous.

18 . The method of claim 1 , wherein the method is conducted at a temperature of 25-100° C.

19 . The method of claim 1 , wherein the method excludes a reverse osmosis process.

20 . The method of claim 1 , wherein the lithium-containing aqueous product solution contains the lithium in at least 99 wt. % purity.

21 . The method of claim 1 , wherein the forward osmosis process does not result in transfer of lithium from the lithium-containing aqueous feed solution into the draw solution and does not result in transfer of ionic species from the draw solution into the lithium-containing aqueous feed solution.

22 . The method of claim 1 , wherein said water-permeable structure is constructed of a water-permeable hydrophilic polymer having a thermal stability of at least 100° C.

23 . The method of claim 22 , wherein said hydrophilic polymer comprises a fluoropolymer, polyether ether ketone (PEEK), polysulfone (PSU), poly(ethersulfone) (PES), polyetherimide (PEI), poly(phenylene sulfide) (PPS), or polybenzimidazole (PBI).

24 . The method of claim 22 , wherein said hydrophilic polymer comprises a fluoropolymer.

25 . The method of claim 24 , wherein said fluoropolymer is selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), perfluorocycloalkenes (PFCAs), perfluoroalkoxy alkanes (PFAs).

26 . The method of claim 22 , wherein said hydrophilic polymer is a hydrophilized version of polyvinylidene fluoride (PVDF).

27 . The method of claim 1 , wherein the coating of the water-permeable hydrophilic polymer has a thickness of no more than 10 microns.

Assignees

• Ut Battelle Llc
• All American Lithium LLC

Inventors

• Bhave Ramesh R
• Deshmane Vishwanath
• Linneen Nicholas N
• Harrison Stephen
• Paranthaman Mariappan
• Moyer Bruce A

Classifications

• B01D63/065

  on the outer surface thereof · CPC title

• B01D71/34 Primary

  Polyvinylidene fluoride · CPC title

• B01D69/02

  characterised by their properties · CPC title

• B01D2325/22

  Thermal or heat-resistance properties · CPC title

• B01D61/005 Primary

  Osmotic agents; Draw solutions · CPC title