VOLTAGE-CONTROLLED ANION EXCHANGE MEMBRANE ENABLING SELECTIVE ION AFFINITIES FOR WATER DESALINATION AND DEVICE CONTAINING THE SAME

• US 20200131058A1
• Filed: 10/11/2019
• Published: 04/30/2020
• Est. Priority Date: 10/26/2018
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Kim, Soo, Mailoa, Jonathan, Kornbluth, Mordechai, Samsonidze, Georgy, Metzger, Michael, Kuppan, Saravannan, Hellstrom, Sondra, Kozinsky, Boris, Craig, Nathan
• Granted Patent: US 11,820,681 B2
• Time in Patent Office: Days
• CPC Class Codes: B01D 2325/16 Membrane materials having positively charged functional groups
• CPC Class Codes: B01D 2325/42 Ion-exchange membranes
• CPC Class Codes: B01D 61/428 Membrane capacitive deionization
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 71/0211 Graphene or derivates thereof
• CPC Class Codes: C02F 1/04 by distillation or evaporation
• CPC Class Codes: C02F 1/4691 Capacitive deionisation
• CPC Class Codes: C02F 2001/46133 characterised by the material
• CPC Class Codes: C02F 2001/46161 Porous electrodes
• CPC Class Codes: C02F 2103/08 Seawater, e.g. for desalination
• CPC Class Codes: C02F 2201/46115 Electrolytic cell with membranes or diaphragms
• CPC Class Codes: C02F 2201/46135 Voltage
• CPC Class Codes: C08J 2325/18 Homopolymers or copolymers of aromatic monomers containing elements other than carbon and hydrogen
• CPC Class Codes: C08J 2349/00 Characterised by the use of homopolymers or copolymers of compounds having one or more carbon-to-carbon triple bonds; Derivatives of such polymers
• CPC Class Codes: C08J 2365/00 Characterised by the use of macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain C08J2307/00 - C08J2357/00, C08J2361/00 take precedence; Derivatives of such polymers
• CPC Class Codes: C08J 2365/02 Polyphenylenes
• CPC Class Codes: C08J 2379/02 Polyamines
• CPC Class Codes: C08J 2381/02 Polythioethers; Polythioether-ethers
• CPC Class Codes: C08J 2429/04 Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
• CPC Class Codes: C08J 2433/12 Homopolymers or copolymers of methyl methacrylate
• CPC Class Codes: C08J 2471/02 : Polyalkylene oxides
• CPC Class Codes: C08J 5/2275 : Heterogeneous membranes

Abstract

A desalination device includes a container, first and second electrodes, an anion exchange membrane (AEM), and a power source. The container contains saline water that has an elevated concentration of dissolved salts. The AEM separates the container into first and second compartments into which the first and second electrodes, respectively, are arranged. The AEM has a continuous porous structure and a plurality of negatively-charged oxygen functional groups coupled to the porous structure. The power source is configured to selectively apply a voltage to one of the first and second electrodes. The AEM has a selective permeability when the voltage is applied such that cations in the saline water solution have a first diffusion rate d₁ therethrough and anions in the saline water solution have a second diffusion rate d₂ therethrough. The first diffusion rate d₁ is less than the second diffusion rate d₂ and greater than or equal to zero.

Claims

1. An anion exchange membrane for a desalination device, comprising:

a membrane support having a porous first side, a porous second side, and a continuous porous structure extending from the first side to the second side, the continuous porous structure including graphene oxide (GO) sheets and a plurality of negatively-charged oxygen functional groups coupled to the GO sheets.

2. The anion exchange membrane of claim 1, wherein the plurality of negatively-charged oxygen functional groups includes one or more of hydroxyl groups and carboxylic groups.

3. The anion exchange membrane of claim 1, wherein the plurality of negatively-charged oxygen functional groups includes one or more of epoxy groups and carbonyl groups.

4. The anion exchange membrane of claim 1, wherein the continuous porous structure includes a mixture of the GO sheets and at least one further polymer that is electronically conductive.

5. The anion exchange membrane of claim 4, wherein the at least one further polymer includes one or more of poly(pyrrole)s (PPY), polyanilines (PANI), poly(thiophene)s (PT), poly(3,4-ethylenedioxythiophene) (PEDOT), poly(p-phenylene sulfide) (PPS), poly(acetylene)s (PAC), and poly(p-phenylene vinylene) (PPV).

6. The anion exchange membrane of claim 1, wherein the continuous porous structure includes a mixture of the GO sheets and at least one further polymer that is ionically conductive and not electronically conductive.

7. The anion exchange membrane of claim 6, wherein the at least one further polymer includes one or more of cross-linked poly-vinyl alcohol (PVA), cross-linked polymethylmethacarylate (PMMA), and polyethylene oxide (PEO).

8. The anion exchange membrane of claim 6, wherein the continuous porous structure includes one or more of graphite, hard carbon, soft carbon, and carbon black.

9. A desalination device, comprising:

a container configured to contain a saline water solution having an elevated concentration of dissolved salts;

a first electrode and a second electrode arranged in a first compartment and a second compartment, respectively, of the container, the first and second electrodes configured to be arranged in fluid communication with the saline water solution;

an anion exchange membrane (AEM) separating the first and second compartments, the AEM having a porous membrane structure and a plurality of negatively-charged oxygen functional groups coupled to the porous membrane structure; and

a power source configured to selectively apply a voltage to one of the first and second electrodes, the AEM having a selective permeability when the voltage is applied such that cations in the saline water solution have a first diffusion rate d₁ therethrough and anions in the saline water solution have a second diffusion rate d₂ therethrough where 0≤

d₁<

d₂.

10. The desalination device of claim 9, wherein the porous membrane structure includes graphene oxide sheets.

11. The desalination device of claim 10, wherein the plurality of negatively-charged oxygen functional groups includes one or more of hydroxyl groups and carboxylic groups.

12. The desalination device of claim 10, wherein the plurality of negatively-charged oxygen functional groups includes one or more of epoxy groups and carbonyl groups.

13. The desalination device of claim 9, wherein the power source is configured to apply a membrane voltage to the AEM via an external circuit, the membrane voltage configured to decrease the first diffusion rate d₁ of the cations through the AEM and increase the second diffusion rate d₂ of the anions through the AEM.

14. The desalination device of claim 13, wherein the membrane voltage is applied in a range from 0 to ±

0.5 V.

15. The desalination device of claim 9, wherein a (de-)sorption voltage of the cations into and out of the AEM is in a range from −

1.0 to 1.5 V relative to a standard hydrogen electrode.

16. The desalination device of claim 9, wherein the porous membrane structure includes mono- and few-layer graphene, the layers having a range from 1 to 8 layers.

17. The desalination device of claim 9, wherein the first and second electrodes are symmetric electrodes that contain an identical intercalation material.

18. The desalination device of claim 17, wherein the intercalation material is one of doped or un-doped cubic spinel MnO₂, tunnel-structured orthorhombic Na₄Mn₉O₁₈, or NaM₂(PO₄)₃ where M=Ti, Mn, Fe, Ni, Cu, or combinations thereof.

19. The desalination device of claim 9, wherein the first and second electrodes are asymmetric electrodes each containing an electrode material comprised of a metal oxide, a concentration of alkali metal within the metal oxide configured to be different between the electrode materials.

20. A method for desalinating water, comprising:

filling first and second compartments of a container with a saline water solution having an elevated concentration of dissolved salts, the container including first and second electrodes arranged in the first and second compartments, respectively, and an anion exchange membrane (AEM) separating the first and second compartments;

operating the first and second electrodes in a forward direction or a reverse direction to release cations into one of the first and second compartments and to remove cations from the other of the first and second compartments; and

applying a membrane voltage to the AEM while operating the first and second electrodes, the membrane voltage decreasing a first diffusion rate of cations through the AEM and increasing a second diffusion rate of anions through the AEM relative to the first and second diffusion rates, respectively, when the membrane voltage is not applied to the AEM.