Electrochemical desalination system

Patent metadata

Field	Value
Publication number	US-2023264140-A1
Application number	US-202318133023-A
Country	US
Kind code	A1
Filing date	Apr 11, 2023
Priority date	Feb 7, 2018
Publication date	Aug 24, 2023
Grant date	—

Abstract

A system comprises an electrodialysis apparatus, which includes first and second reservoirs, wherein a salt concentration in the first reservoir reduces below a threshold concentration and salt concentration in the second reservoir increases during an operation mode. A first electrode comprises a first solution of a first redox-active electrolyte material, and a second electrode comprises a second solution of a second redox-active electrolyte material. In a first reversible redox reaction between the first electrode and first electrolyte material at least one ion is accepted from the first reservoir, and in a second reversible redox reaction between the second electrode and second electrolyte material at least one ion is driven into the second reservoir. A first type of membrane is disposed between the first and second reservoirs, and a second type of membrane, different from the first type, is disposed between the respective electrodes and reservoirs.

First claim

What is claimed is:

1 . A method for separating a solvent from a salt dissolved in the solvent, comprising:
providing an electrodialysis apparatuses comprising:
a first reservoir comprising a first input and a first output, wherein the salt dissolved in the solvent in the first reservoir is reduced below a threshold concentration during an operation mode;
a second reservoir comprising a second input and a second output, wherein the salt dissolved in the solvent in the second reservoir increases in concentration during the operation mode;
a first electrode contacting a first aqueous solution of a first redox-active electrolyte material and configured to have a first reversible redox reaction with the first redox-active electrolyte material, and the first redox-active electrolyte material accepts a salt ion of the salt from the solvent in the first reservoir;
a second electrode contacting a second aqueous solution of a second redox-active electrolyte material and configured to have a second reversible redox reaction with the second redox-active electrolyte material, and drive a salt ion of the salt from the second redox-active electrolyte material into the solvent in the second reservoir, wherein at least one of the first and second redox-active electrolyte materials comprises a ferrocene derivative that is chemically stable in oxidized and reduced forms to reaction with oxygen gas;
a first type of membrane disposed between the first and second reservoirs;
a second type of membrane, different from the first type, disposed between the first electrode and the first reservoir and disposed between the second electrode and the second reservoir;
transporting solvent having a first concentration of dissolved salt into the first and second reservoirs; operating the electrodialysis apparatus in a mode to generate a first stream having a second concentration of the dissolved salt that is lower than the first concentration of the dissolved salt and to generate a second stream having a third concentration of the dissolved salt that is higher than the first concentration of the dissolved salt; and transporting the first stream through a switching unit to a further desalination system to generate a further stream having a final concentration of the dissolved salt that is lower than second concentration of the dissolved salt, wherein the further desalination system uses a solvent treatment process different from the electrodialysis apparatus.

2 . The method according to claim 1 , wherein the first aqueous solution and the second aqueous solution are the same and the first and second aqueous solutions are circulated between the first electrode and the second electrode during the operation mode and the electrodialysis apparatus operates in electrodialysis mode.

3 . The method according to claim 1 , wherein the first aqueous solution is an anolyte and the second aqueous solution is a catholyte, and the anolyte and the catholyte are different chemical species.

4 . The method according to claim 3 , wherein the electrodialysis apparatus operates in charge mode or discharge mode.

5 . The method according to claim 3 , wherein the electrodialysis apparatus operates alternately between charge mode and discharge mode.

6 . The method according to claim 1 , further comprising operating the electrodialysis apparatus in a discharge mode to generate power and powering at least a portion of the further desalination system with the power generated from the electrodialysis apparatuses.

7 . The method according to claim 1 , wherein the switching unit is coupled to the first and second outputs of the first and second reservoirs and at least one output of the switching unit is coupled to the input of the further desalination system.

8 . The method according to claim 1 , wherein the further desalination system is a reverse osmosis system.

9 . The method according to claim 1 , wherein the further desalination system is a thermal evaporation system.

10 . The method according to claim 1 , wherein the further desalination system is a capacitive deionization system.

11 . The method according to claim 1 , wherein the third concentration of the dissolved salt is less than 0.5 ppt.

12 . The method according to claim 1 , wherein the electrodialysis apparatuses comprises a first electrodialysis apparatus and a second electrodialysis apparatus, the first electrodialysis apparatus operating alternately between charge mode and discharge mode, and the second electrodialysis apparatus operating in electrodialysis mode, and a further switching unit coupled to a first and second outputs of first and second reservoirs of the first electrodialysis apparatus, and the second electrodialysis apparatus is coupled to at least one output of the further switching unit.

13 . The method according to claim 12 , wherein the further desalination system is coupled to the second electrodialysis apparatus through the switching unit.

14 . The method according to claim 13 , further comprising powering at least a portion of the further desalination system with the power generated from the first electrodialysis apparatuses.

15 . The method according to claim 12 , wherein the first concentration of dissolved salt is about 35 ppt, and the final concentration of the dissolved salt is about 0.5 ppt.

Assignees

• Palo Alto Res Ct Inc

Inventors

• Beh Eugene S
• Rivest Jessica Louis Baker
• Benedict Michael
• Karatay Elif

Classifications

• B01D61/461

  comprising only a single cell, only one anion or cation exchange membrane or one pair of anion and cation membranes · CPC title

• B01D53/1425 Primary

  Regeneration of liquid absorbents · CPC title

• H01M8/227

  Dialytic cells or batteries; Reverse electrodialysis cells or batteries · CPC title

• B01D61/46

  Apparatus therefor · CPC title

• B01D53/263

  by absorption · CPC title