Devices and methods for electric field driven on-demand separation of liquid-liquid mixtures

Patent metadata

Field	Value
Publication number	US-9834459-B2
Application number	US-201314401778-A
Country	US
Kind code	B2
Filing date	May 17, 2013
Priority date	May 17, 2012
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

Devices and methods for electric field driven on-demand separation of liquid-liquid mixtures are provided. For example, methods for separating liquid-liquid mixtures, such as free oil and water, oil-in-water emulsions and water-in-oil emulsions, are provided that have separation efficiencies up to about 99.9%. The liquid-liquid mixture is contacted with a separator membrane assembly comprising a separator membrane formed of a porous oleophobic (or superoleophobic) material and an electrically conductive member. An electrical potential is applied across the porous oleophobic (or superoleophobic) material of the separator membrane to facilitate passage and separation of at least a portion of the first component through the separator membrane. Separation devices and such separator membrane assemblies are also provided.

First claim

What is claimed is:

1. A method of separating a liquid-liquid mixture comprising:
contacting the liquid-liquid mixture with a separator membrane comprising a porous oleophobic material, wherein the liquid-liquid mixture comprises a first component and a second distinct component and the separator membrane has a first operating condition and a second operating condition, wherein in the first operating condition electrical potential is absent across the separator membrane, so that none of the liquid-liquid mixture passes through the separator membrane, and in the second operating condition, electrical potential is applied to the separator membrane to facilitate passage of the first component from the liquid-liquid mixture through the separator membrane, while the second distinct component of the liquid-liquid mixture does not pass through the separator membrane; and
applying an electrical potential across the porous oleophobic material of the separator membrane to facilitate passage and separation of at least a portion of the first component through the separator membrane, while the second distinct component of the liquid-liquid mixture does not pass through the separator membrane.

2. The method of claim 1 , wherein the first component is present at an initial amount in the liquid-liquid mixture, so that greater than or equal to about 85 weight % of the initial amount of the first component is separated from the liquid-liquid mixture after the applying of the electrical potential across the porous oleophobic material of the separator membrane.

3. The method of claim 2 , wherein the contacting and the applying of the electrical potential across the porous oleophobic material of the separator membrane occurs in a single stage, so that the separation process of the first component occurs as a single process step.

4. The method of claim 1 , wherein the first component is hydrophilic or polar and is present at an initial amount in the liquid-liquid mixture and greater than or equal to about 99 weight % of the initial amount of the first component is separated from the liquid-liquid mixture after the applying of the electrical potential across the porous oleophobic material of the separator membrane.

5. The method of claim 1 , wherein the first component is water and the second component is oil and the liquid-liquid mixture is a surfactant stabilized emulsion, wherein greater than or equal to about 99 weight % of the initial amount of the water is separated from the surfactant stabilized emulsion after applying electrical potential across the porous oleophobic material of the separator membrane.

6. The method of claim 1 , wherein the contacting occurs by gravity-feeding the liquid-liquid mixture to the separator membrane at ambient temperature and pressure conditions.

7. The method of claim 1 , wherein the electrical potential applied across the porous oleophobic material of the separator membrane is about 0.01 to about 10 kV.

8. The method of claim 1 , wherein the porous oleophobic material comprises a low surface energy material comprising 1H, 1H, 2H, 2H-hetadecafluorodecyl polyhedral oligomeric silsequioxane (F-POSS) and a polymer selected from the group consisting of: poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), perfluorinated polymers, cross-linked poly(dimethyl)siloxane (PDMS), and combinations thereof.

9. The method of claim 1 , wherein the first component comprises a polar molecule and the second component comprises a non-polar molecule.

10. The method of claim 1 , wherein the first component is a first molecule having a first polarity and the second component is a second molecule having a second polarity, wherein the first polarity is greater than the second polarity and the actuatable separator membrane separates greater than or equal to about 90 weight % of the initial amount of the first component from the liquid-liquid mixture.

11. A separator membrane assembly comprising:
(i) a separator membrane comprising at least one layer comprising a porous oleophobic material capable of separating a liquid-liquid mixture comprising a first component and a second component, the separator membrane having a first operating condition and a second operating condition; and
(i) an electrically conductive member for applying the electrical potential across the at least one layer of porous oleophobic material, wherein in the first operating condition electrical potential across the separator membrane is absent, so that none of the liquid-liquid mixture passes through the separator membrane, and in the second operating condition, the electrical potential is applied via the electrically conductive member to the separator membrane so as to facilitate passage of a first component from the liquid-liquid mixture through the separator membrane, while a second component of the liquid-liquid mixture does not pass through the sparator membrane.

12. The separator membrane assembly of claim 11 , wherein the porous oleophobic material comprises a low surface energy material selected from the group consisting of: 1H, 1H, 2H, 2H-heptadecafluorodecyl polyhedral oligomeric silsequioxane (F-POSS), graphite fluoride, perfluorodecanethiol, perfluorodecyl trichlorosilane and perflorodecyl dimethyl chlorosilane, polytetrafluoroethylene, fluorosurfactants, fluorosilanes, derivatives, and combinations thereof.

13. The separator membrane assembly of claim 11 , wherein the porous oleophobic material is a superoleophobic porous material having an apparent advancing dynamic contact angle of greater than or equal to about 150° for a preselected oil.

14. The separator membrane assembly of claim 12 , wherein the porous oleophobic material further comprises a polymer selected from the group consisting of: poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), perfluorinated polymers, cross-linked poly(dimethyl)siloxane (PDMS), derivatives, and combinations thereof.

15. The separator membrane assembly of claim 11 , wherein the porous oleophobic material comprises a polymeric material formed from cross-linked poly(dimethyl)siloxane (PDMS) and a low surface energy material comprising 1H, 1H, 2H, 2H-hetadecafluorodecyl polyhedral oligomeric silsequioxane (F-POSS).

16. The separator membrane assembly of claim 11 , further comprising a plurality of layers of the porous oleophobic material that form a stack, and wherein the electrically conductive member is an electrically conductive porous material in electrical contact with the stack.

17. The separator membrane assembly of claim 11 , wherein the porous oleophobic material comprises a porous material selected from the group consisting of screen, mesh, paper, woven cloth, non-woven cloth, fabric, fiber, foam, molecular sieves, entangled nanowires, electrospun polymeric nanofibers, and combinations thereof.

18. The separator membrane assembly of claim 11 , wherein an average pore size diameter of a plurality of pores in the porous oleophobic material is greater than or equal to about 10 nm to less than or equal to about 1 mm.

19. A separation device comprising:
a separator membrane assembly for processing a liquid-liquid mixture comprising a first component that is polar or hydrophilic and a second component that is non-polar or hydrophobic that comprises:
(i) a separator membrane comprising at least one layer comprising a porous oleophobic material; and
(ii) an electrically conductive member capable of applying electrical potential across the at least one layer of porous oleophobic material; wherein the separator membra

Assignees

• Univ Michigan Regents

Inventors

• Tuteja Anish
• Kota Arun Kumar
• Kwon Gibum

Classifications

• B01D17/06 Primary

  Separation of liquids from each other by electricity · CPC title

• C02F1/4696 Primary

  electrophoresis · CPC title

• B01D61/425

  Electro-ultrafiltration · CPC title

• B01D17/085

  with membranes · CPC title