Advanced filtration membranes using chitosan and graphene oxide

• US 10,596,525 B2
• Filed: 08/07/2017
• Issued: 03/24/2020
• Est. Priority Date: 08/07/2017
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Inventors: Medina, Victor F, Griggs, Christopher S, Mattei-Sosa, Jose, Petery, Brooke, Gurtowski, Luke
• Primary Examiner(s): Spies, Bradley R
• Application Number:
  US15/671,043
• Publication Number:
  US 20190039026A1
• Time in Patent Office: 960 Days
• Field of Search: None
• CPC Class Codes: B01D 2319/06 Use of membranes of different materials or properties within one module
• CPC Class Codes: B01D 2323/12 Specific ratios of components used
• CPC Class Codes: B01D 2323/21826 Acids, e.g. acetic acid
• CPC Class Codes: B01D 2323/21827 Salts
• CPC Class Codes: B01D 2323/30 Cross-linking
• CPC Class Codes: B01D 2323/52 Use of a mould
• CPC Class Codes: B01D 2325/04 Characteristic thickness
• CPC Class Codes: B01D 63/10 Spiral-wound membrane modules
• CPC Class Codes: B01D 67/0079 Manufacture of membranes comprising organic and inorganic components
• CPC Class Codes: B01D 67/00793 Dispersing a component, e.g. as particles or powder, in another component
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 69/10 Supported membranes; Membrane supports
• CPC Class Codes: B01D 69/12 Composite membranes; Ultra-thin membranes
• CPC Class Codes: B01D 69/1216 Three or more layers
• CPC Class Codes: B01D 69/148 Organic/inorganic mixed matrix membranes
• CPC Class Codes: B01D 71/021 Carbon
• CPC Class Codes: B01D 71/0211 Graphene or derivates thereof
• CPC Class Codes: B01D 71/024 Oxides
• CPC Class Codes: B01D 71/08 Polysaccharides
• CPC Class Codes: B01D 71/74 Natural macromolecular material or derivatives thereof B01D71/08, B01D71/24 take precedence
• CPC Class Codes: C02F 1/44 : by dialysis, osmosis or reverse osmosis general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268
• CPC Class Codes: C02F 1/441 : by reverse osmosis
• CPC Class Codes: C02F 2303/04 : Disinfection
• CPC Class Codes: C02F 2303/20 : Prevention of biofouling

Abstract

A composition of five parts by mass of chitosan and one part graphene oxide is suspended in water. The composition may be used to form filtration layers of any size or shape and may be reinforced by additional layers. The composition may be used to construct a large filtration apparatus of any size or shape and may be used to form highly resilient, antimicrobial structures and surfaces for a variety of applications.

Claims

1. A method of making a highly-resilient fluid and gas apparatus comprised of the steps of:

protonating a quantity chitosan to create protonated chitosan;

mixing a quantity of granular graphene oxide with said protonated chitosan to create a solution;

filling a molding structure with a quantity of said solution;

evaporating said solution on a surface to create a membrane having a target thickness; and

placing said membrane between two layers;

wherein said quantity of chitosan and said quantity of graphene have a ratio between 4;

1 and 6;

1; and

wherein a target thickness ranges from 5 to 200 microns and a target flow rate of at least 1.5 LMH is achieved.

2. The method of claim 1 wherein said quantity of chitosan and said quantity of graphene have a 5:

1 ratio.

3. The method of claim 1 in which the step of protonating includes the step of creating a homogeneous mixture by rendering the chitosan water soluble.

4. The method of claim 1 wherein said layers are cellulose layers.

5. The method of claim 1 wherein said layers are comprised a material selected from the group consisting of paper, glass wool and permeable plastic.

6. The method, of claim 1 wherein the step of protonating further includes combining said quantity of chitosan with an acid.

7. The method of claim 6 wherein said acid is selected from the group consisting of Acetic Acid, Malic Acid, Succinic Acid, Glycolic Acid, Oxalic Acid, Adipic Acid, Citric Acid, Formic Acid Carboxylic Acid, Sulfonic Acid, Muriatic Acid and Tannic Acid.

8. The method of claim 6 wherein said acid is organic.

9. The method of claim 1 which further includes placing two or more of said membranes in serial configuration to accomplish a multi-staged filtration process.

10. The method of claim 1 wherein a target rejection rate of at least 97.5% is achieved.