Method for removing organic pollutants from contaminated water using polystyrene-carbon nanofiber composition made from post-consumer waste

Patent metadata

Field	Value
Publication number	US-11807554-B2
Application number	US-201816211775-A
Country	US
Kind code	B2
Filing date	Dec 6, 2018
Priority date	Dec 6, 2018
Publication date	Nov 7, 2023
Grant date	Nov 7, 2023

Abstract

Polystyrene waste, such as Styrofoam® waste, and carbon nanofibers may be used to produce highly hydrophobic compositions or composites that can separate oil and water. Methods for purifying an aqueous solution may include: passing the aqueous solution, including a hydrophobic organic substance, over or through a surface including a polystyrene-CNF composition, thereby producing an aqueous product including less of the hydrophobic organic substance; and optionally, passing the aqueous product over or through the surface at least one more time.

First claim

The invention claimed is:

1. A method for purifying an aqueous solution, the method comprising:
passing the aqueous solution, comprising a hydrophobic organic substance, over or through a surface comprising a polystyrene-carbon nanofiber (CNF) composition, thereby producing an aqueous product comprising less of the hydrophobic organic substance,
wherein a polystyrene of the polystyrene-CNF comprises post-consumer waste collapsed polystyrene foam,
wherein a CNF of the polystyrene-CNF is associated with the polystyrene by sonicating a mixture of the CNF and the polystyrene in softened or collapsed form,
wherein the post-consumer waste polystyrene is contaminated with sugar, starch, protein, nucleic acid, lipid, other food component, paint, ink, dye paper, or non-polystyrene plastic contaminant, in a range of from 0.001 and 5 wt. %.

2. The method of claim 1 , wherein the aqueous solution comprises oil or a further hydrocarbon.

3. The method of claim 1 , wherein the polystyrene-CNF composition is in the form of a membrane or a filter having a surface exposed to the aqueous solution.

4. The method of claim 1 , further comprising:
producing the polystyrene-CNF from the post-consumer waste collapsed polystyrene foam.

5. The method of claim 1 , further comprising:
producing the polystyrene-CNF from the post-consumer waste collapsed polystyrene foam,
wherein the post-consumer waste collapsed polystyrene foam is contaminated with the sugar, starch, protein, nucleic acid, lipid, other food component, paint, ink, dye paper, or non-polystyrene plastic contaminant, in a range of from 0.001 and 0.1 wt. %.

6. The method of claim 1 , wherein the aqueous solution is water comprising the hydrophobic organic substance in a range of from 50 to 250 ppm,
wherein the hydrophobic organic substance is oil or an oily waste.

7. The method of claim 1 , further comprising:
phase separating one or more hydrophobic oils or other organic substances from the aqueous solution, to obtain a separated aqueous phase, prior to contacting, then contacting the separated aqueous phase of the aqueous solution with the surface of the polystyrene-CNF composition.

8. The method of claim 1 , further comprising:
passing the aqueous product over or through the surface at least one more time.

9. The method of claim 1 , wherein the surface of the composition has a water contact angle in a range of from 80 to 160°.

10. The method of claim 1 , wherein the surface of the composition has a surface area in a range of from 50 to 100 m 2 /g.

11. The method of claim 1 , wherein the polystyrene consists of post-consumer waste polystyrene.

12. The method of claim 1 , wherein the polystyrene is post-consumer waste polystyrene that is contaminated sugar, starch, protein, nucleic acid, lipid, other food component, paint, ink, dye, paper, or non-polystyrene plastic contaminant, in a range of from 0.02 and 0.1 wt. %.

13. The method of claim 1 , wherein a weight ratio of the polystyrene to the CNF is in a range of from 1:5 to 1:10.

14. The method of claim 1 , wherein a weight ratio of the polystyrene to the CNF is in a range of from >1:10 to 1:50.

15. The method of claim 1 , wherein the polystyrene is expanded or extruded polystyrene.

16. The method of claim 1 , wherein the polystyrene-CNF composition comprises the CNF in a range of from 2 to 20 wt. %, relative to total polystyrene-CNF composition weight.

17. The method of claim 1 , wherein the polystyrene-CNF composition comprises the CNF in a range of from 4 to 10 wt. %, relative to total polystyrene-CNF composition weight.

18. The method of claim 1 , wherein the polystyrene is not crosslinked.

19. The method of claim 1 , wherein the polystyrene is unmodified polystyrene.

20. The method of claim 1 , wherein the passing is in liquid phase.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Awadh Tawfik Abdo Saleh
• Baig Nadeem

Classifications

• C02F1/288 Primary

  using composite sorbents, e.g. coated, impregnated, multi-layered · CPC title

• C08J3/2053

  the additives only being premixed with a liquid phase · CPC title

• C08J11/26

  containing carboxylic acid groups, their anhydrides or esters · CPC title

• C08K7/04

  inorganic · CPC title

• C02F2101/322

  Volatile compounds, e.g. benzene · CPC title