Carbon nanofiber grafted polyurethane composite for separation of nonpolar components from water

Patent metadata

Field	Value
Publication number	US-11117115-B2
Application number	US-201916351720-A
Country	US
Kind code	B2
Filing date	Mar 13, 2019
Priority date	Mar 13, 2019
Publication date	Sep 14, 2021
Grant date	Sep 14, 2021

Abstract

A composite of polyurethane foam grafted with carbon nanofibers is described. This composite foam may be made by contacting and drying a polyurethane foam with a suspension of carbon nanofibers and then drying. Additional carbon nanofiber layers may be added with repeated contacting. The composite film has a high surface area of 276 m2/g and a hydrophobic character that may be exploited for separating an oil phase from water.

First claim

The invention claimed is:

1. A carbon nanofiber (CNF) grafted polyurethane composite, comprising:
a polyurethane foam coated with a layer of carbon nanofibers,
wherein a BET surface area is in a range of 220-320 m 2 /g, and
wherein an apparent contact angle with water is 140°-170°.

2. The CNF grafted polyurethane composite of claim 1 , wherein the layer of carbon nanofibers is porous with an average pore size of 2-5 nm.

3. The CNF grafted polyurethane composite of claim 1 , wherein the polyurethane foam has an average pore diameter in a range of 200-850 μm.

4. The CNF grafted polyurethane composite of claim 1 , wherein the carbon nanofibers have an average length in a range of 5-20 μm and an average thickness in a range of 5-15 nm.

5. The CNF grafted polyurethane composite of claim 1 , wherein the layer of carbon nanofibers further comprises carbon nanoparticles having an average diameter in a range of 1-2 μm.

6. The CNF grafted polyurethane composite of claim 1 , wherein at least 70% of the surface of the polyurethane foam is coated with the layer of carbon nanofibers.

7. A method of making the CNF grafted polyurethane composite of claim 1 , comprising:
contacting a polyurethane foam with a suspension of carbon nanofibers in an alcohol to produce a wet scaffold, and
drying the wet scaffold to produce the CNF grafted polyurethane composite.

8. The method of claim 7 , wherein the polyurethane foam has a surface area in a range of 5-20 m 2 /g.

9. The method of claim 7 , wherein the carbon nanofibers are present in the suspension at a concentration of 0.1-5 mg/mL.

10. The method of claim 7 , wherein the alcohol is methanol, ethanol, butanol, or isopropanol.

11. The method of claim 7 , wherein the contacting is done for a period of 3-60 min.

12. The method of claim 7 , wherein the drying is at a temperature of 50-80° C. for a period of 12-24 h.

13. The method of claim 7 , wherein the contacting and drying are each repeated two more times on the CNF grafted polyurethane composite.

14. A method of separating a nonpolar compound from an aqueous solution in a mixture, the method comprising:
contacting the mixture with the CNF grafted polyurethane composite of claim 1 ,
wherein the CNF grafted polyurethane composite adsorbs 20-50 times its weight of the nonpolar compound.

15. The method of claim 14 , wherein the nonpolar compound is at least one selected from the group consisting of hexane, heptane, toluene, xylene, and a petroleum-derived liquid.

16. The method of claim 14 , wherein the nonpolar compound is petrol.

17. The method of claim 14 , wherein the CNF grafted polyurethane composite adsorbs less than 20% of its weight of the aqueous solution.

18. The method of claim 14 , wherein the contacting involves filtering the mixture through the CNF grafted polyurethane composite.

19. The method of claim 14 , further comprising:
compressing the CNF grafted polyurethane composite after the contacting to produce a discharged polyurethane composite, and
reusing the discharged polyurethane composite.

20. The method of claim 19 , wherein the discharged polyurethane composite comprises at least 95 wt % carbon nanofibers relative to a weight of carbon nanofibers in the CNF grafted polyurethane composite.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Awadh Tawfik Abdo Saleh
• Baig Nadeem

Classifications

• C02F2101/32

  Hydrocarbons, e.g. oil · CPC title

• B01J20/3217

  Resulting in a chemical bond between the coating or impregnating layer and the carrier, support or substrate, e.g. a covalent bond · CPC title

• B01J20/324

  containing free carbon, e.g. activated carbon · CPC title

• B01J20/3416

  of sorbents or filter aids comprising free carbon, e.g. activated carbon · CPC title

• C09K3/32

  for absorbing liquids to remove pollution, e.g. oil, gasoline, fat · CPC title