Filtering article containing titania nanotubes

• US 10,130,917 B2
• Filed: 02/04/2014
• Issued: 11/20/2018
• Est. Priority Date: 02/06/2013
• Status: Active Grant

• Current Assignee: Northeastern University
• Original Assignee: Northeastern University
• Inventors: Panaitescu, Eugen, Menon, Latika
• Primary Examiner(s): Menon, Krishnan S
• Assistant Examiner(s): Huang, Ryan B
• Application Number:
  US14/765,229
• Publication Number:
  US 20150367289A1
• Time in Patent Office: 1,750 Days
• Field of Search: None
• CPC Class Codes: B01D 15/08 Selective adsorption, e.g. chromatography
• CPC Class Codes: B01D 2323/00 Details relating to membrane preparation
• CPC Class Codes: B01D 2325/20 Specific permeability or cut-off range
• CPC Class Codes: B01D 2325/36 Hydrophilic membranes
• CPC Class Codes: B01D 67/0044 by chemical reaction
• CPC Class Codes: B01D 67/0065 by anodic oxidation
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 69/04 Tubular membranes
• CPC Class Codes: B01D 69/043 characterised by the tube diameter
• CPC Class Codes: B01D 71/024 Oxides
• CPC Class Codes: C01G 23/047 Titanium dioxide
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/13 Nanotubes
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C25D 11/02 Anodisation
• CPC Class Codes: C25D 11/26 of refractory metals or alloys based thereon
• CPC Class Codes: C25D 7/04 Tubes; Rings; Hollow bodies

Abstract

Provided in one embodiment is a filtering article, comprising: powders comprising bundles of nanotubes, each bundle comprising hollow titania nanotubes. Embodiments of the methods of making and using the filtering articles are also provided.

Claims

1. A filtering article comprising:

i) a pellet of powders, the powders comprising bundles of hollow titania nanotubes; and

ii) a freestanding array of hollow titania nanotubes aligned in parallel,

wherein the pellet and the freestanding array are integrated together in the filtering article.

2. The filtering article of claim 1, wherein in the pellet of powders,

at least some of the bundles have a length of at least about 1 micron.

3. The filtering article of claim 1,

wherein the freestanding array has

a topographical surface area of at least 1 cm².

4. The filtering article of claim 1, wherein the pellet has a diameter of at least 1 cm.

5. The filtering article of claim 1, wherein a side of the filtering article exposed to a material to be filtered comprises the freestanding array.

6. The filtering article of claim 1, wherein at least some of the hollow nanotubes of the pellet or freestanding array are functionalized by at least one of a hydrophobic material and an oleophobic material.

7. The filtering article of claim 1, wherein the filtering article

is permeable to water at transmembrane pressures below about 1 atm.

8. The filtering article of claim 1, wherein the hollow titania nanotubes of the pellet or freestanding array comprise anodized titanium.

9. An article comprising the filtering article of claim 1, wherein the filtering article is at least one of a water filtration membrane, a water-oil separation membrane, and a liquid chromatography column.

10. The filtering article of claim 1, wherein in the pellet of powders, at least some of the bundles have a width of at least 1 micron.

11. The filtering article of claim 1, wherein in the pellet of powders, at least some of the hollow titania nanotubes have a diameter between about 25 nm and about 50 nm.

12. The filtering article of claim 1, wherein in the freestanding array, at least some of the hollow titania nanotubes have a diameter between about 60 nm and about 300 nm.

13. The filtering article of claim 1, wherein in the freestanding array, at least some of the hollow titania nanotubes have a length of at least about 1 micron.

14. The filtering article of claim 1, wherein the pellet has a thickness of at least 1 mm.

15. The filtering article of claim 1, wherein the freestanding array is on top of the pellet, and the array and pellet are sealed at an edge.

16. The filtering article of claim 1, wherein the pellet and the freestanding array are separate components in the filtering article such that a fluid to be filtered passes through the pellet and the freestanding array in consecutive filtering components.

17. A method of separating a filtrate from a fluid containing the filtrate, the method comprising:

exposing the fluid to a filtering article, wherein the filtering article comprises;

i) a pellet of powders, the powders comprising bundles of hollow titania nanotubes; and

ii) a freestanding array of hollow titania nanotubes aligned in parallel;

wherein the pellet and the freestanding array are integrated together in the filtering article; and

wherein the fluid is exposed to the freestanding array prior to the powders.

18. The method of claim 17, wherein exposing the fluid to a filtering article is carried out at a pressure below about 6 atm.

19. A method of making a filtering article, the method comprising:

(i) anodizing titanium in an aqueous electrolyte solution to form powders comprising bundles of hollow titania nanotubes, the aqueous electrolyte solution comprising at least about 1 mM chloride and having a pH from about 1 to about 7;

(ii) forming the powders into a pellet;

(iii) anodizing titanium in a non-aqueous electrolyte solution to form a freestanding array of hollow titania nanotubes aligned in parallel, the non-aqueous electrolyte solution comprising at least about 1 mM fluoride; and

(iv) integrating the pellet and freestanding array together to make the filtering article.

20. The method of claim 19, further comprising functionalizing at least some of the hollow titania nanotubes of the pellet or freestanding array with at least one of a hydrophobic material and an olephobic material.