Water treatment method for adsorbing metal ions

Patent metadata

Field	Value
Publication number	US-12180100-B2
Application number	US-202418768193-A
Country	US
Kind code	B2
Filing date	Jul 10, 2024
Priority date	Aug 23, 2021
Publication date	Dec 31, 2024
Grant date	Dec 31, 2024

Abstract

A method of removing a metal ion from water is disclosed. The method includes treating the water with a nanocomposite to absorb the metal ion with the nanocomposite, forming a polymer-metal ion composite and removing the polymer-metal ion composite from the water. The nanocomposite includes aluminum oxide dispersed in a matrix of an uncrosslinked graft copolymer that includes a chitosan backbone and side chains of poly (itaconic acid) grafted to the chitosan backbone. The chitosan backbone has a plurality of amino groups that are acetylated by itaconic acid.

First claim

The invention claimed is:

1. A water treatment method for adsorbing metal ions from water, comprising:
adjusting the pH of the water to from 6 to 7;
treating the water with a nanocomposite to absorb the metal ion with the nanocomposite and form a polymer-metal ion composite,
wherein the nanocomposite is in the form of particles comprising aluminum oxide dispersed in a matrix of an uncrosslinked graft copolymer that includes a chitosan backbone and side chains of poly (itaconic acid) grafted to the chitosan backbone, the chitosan backbone having a plurality of amino groups that are acetylated by itaconic acid; and
removing the polymer-metal ion composite from the water.

2. The method of claim 1 , further comprising
acidifying the polymer-metal ion composite to remove the metal ion from the polymer-metal ion composite and regenerate the nanocomposite.

3. The method of claim 2 , further comprising
treating the water with the nanocomposite formed by the acidifying to remove the metal ion from the water.

4. The method of claim 2 , wherein the metal ion is Cu 2+ ion and the acidifying includes mixing the polymer-metal ion composite with nitric acid to remove the Cu 2+ ion from the polymer-metal ion composite.

5. The method of claim 1 , further comprising
forming the uncrosslinked graft copolymer by:
adding sodium bisulfite, potassium persulphate and itaconic acid to chitosan in acetic acid to form a solution;
heating the solution to an elevated temperature for a period of time to form uncrosslinked graft copolymer;
filtering the solution to obtain a crude product comprising the uncrosslinked graft copolymer and unreacted chitosan; and
removing the unreacted chitosan from the crude product by Soxhlet extraction with ethanol to obtain the uncrosslinked graft copolymer.

6. The method of claim 5 , wherein:
the sodium bisulfite has a concentration of 0.01-0.03 M in the solution;
the potassium persulphate has a concentration of 0.01-0.03 M in the solution;
the chitosan has a concentration around 0.1 M in the solution;
the itaconic acid has a concentration of 0.1-0.2 M in the solution;
the elevated temperature is in the range of 30-60° C.; and
the period of time is between 1 hour and 6 hours.

7. The method of claim 1 , further comprising:
forming the nanocomposite by solution casting a mixture of the uncrosslinked graft copolymer and aluminum oxide nanoparticles.

8. The method of claim 7 , further comprising:
dissolving the uncrosslinked graft copolymer in acetic acid to obtain a polymer solution;
adjusting the pH of the polymer solution to the range of 6-7;
adding a suspension of aluminum oxide nanoparticles in water portion-wise to the polymer solution to form the mixture;
stirring the mixture;
casting the mixture onto a carrier substrate; and
drying the cast mixture to form the nanocomposite film.

9. The method of claim 8 , wherein the aluminum oxide nanoparticles have an average particle size of less than 50 nm.

10. The method of claim 1 , wherein the treating comprises immersing the nanocomposite in the water and shaking the water at an elevated temperature.

11. The method of claim 10 , further comprising:
shaking the water between 30° C. and 60° C. at a speed of 100-300 rpm for 1-3 hours.

12. The method of claim 1 , wherein the metal ion includes at least one of Cu 2+ and Zn 2+ .

13. The method of claim 1 , wherein the metal ion includes at least one of Na + and K + .

14. The method of claim 1 , wherein the side chains of poly (itaconic acid) are grafted to the chitosan backbone via C6 hydroxyl groups.

15. The method of claim 1 , wherein a grafting density of itaconic acid is between 20 wt. % and 60 wt. %, the grafting density including poly (itaconic acid) grafted to the chitosan backbone and the itaconic acid acetylating the plurality of amino groups of the chitosan backbone.

Assignees

• Univ Imam Abdulrahman Bin Faisal

Inventors

• Abdel-Naby Abir Said Ibrahim

Classifications

• C08L5/08 Primary

  Chitin; Chondroitin sulfate; Hyaluronic acid; Derivatives thereof · CPC title

• C02F2101/20

  Heavy metals or heavy metal compounds · CPC title

• C02F2305/08

  Nanoparticles or nanotubes · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• C02F1/683

  by addition of complex-forming compounds · CPC title