# US 12,180,100 B2 · Water treatment method for adsorbing metal ions > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,180,100 B2 - Document ID: US12180100B2 - Status: Granted - Kind: B2 - Application number: 18/768,193 - Filed: 2024-07-10 - Published: 2024-10-31 - Granted: 2024-12-31 - Earliest claimed: 2021-08-23 - Assignees: Imam Abdulrahman Bin Faisal University - Applicants: Imam Abdulrahman Bin Faisal University - Inventors: Abir Said Ibrahim Abdel-Naby - Web page: https://patentgrep.com/patent/US12180100B2 ## CPC - C02F 1/62: Heavy metal compounds - C02F 1/288: {using composite sorbents, e.g. coated, impregnated, multi-layered} - C02F 1/683: {by addition of complex-forming compounds} - C08B 37/003: {Chitin, i.e. 2-acetamido-2-deoxy-(beta-1,4)-D-glucan or N-acetyl-beta-1,4-D-glucosamine; Chitosan, i.e. deacetylated product of chitin or (beta-1,4)-D-glucosamine; Derivatives thereof} - C08L 5/08: Chitin; Chondroitin sulfate; Hyaluronic acid; Derivatives thereof - B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites - C02F 2101/20: Heavy metals or heavy metal compounds - C02F 2305/08: Nanoparticles or nanotubes - C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes) - C08B: POLYSACCHARIDES; DERIVATIVES THEREOF (polysaccharides containing less than six saccharide radicals attached to each other by glycosidic linkages C07H; fermentation or enzyme-using processes C12P19/00; sugar industry C13; production of cellulose D21) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES ## 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. ## Claims ### Claim 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. ### Claim 2 (depends on 1) 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. ### Claim 3 (depends on 2) 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. ### Claim 4 (depends on 2) The method of claim 2, wherein the metal ion is Cu2+ ion and the acidifying includes mixing the polymer-metal ion composite with nitric acid to remove the Cu2+ ion from the polymer-metal ion composite. ### Claim 5 (depends on 1) 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. ### Claim 6 (depends on 5) 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. ### Claim 7 (depends on 1) The method of claim 1, further comprising: forming the nanocomposite by solution casting a mixture of the uncrosslinked graft copolymer and aluminum oxide nanoparticles. ### Claim 8 (depends on 7) 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. ### Claim 9 (depends on 8) The method of claim 8, wherein the aluminum oxide nanoparticles have an average particle size of less than 50 nm. ### Claim 10 (depends on 1) The method of claim 1, wherein the treating comprises immersing the nanocomposite in the water and shaking the water at an elevated temperature. ### Claim 11 (depends on 10) 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. ### Claim 12 (depends on 1) The method of claim 1, wherein the metal ion includes at least one of Cu2+ and Zn2+. ### Claim 13 (depends on 1) The method of claim 1, wherein the metal ion includes at least one of Na+ and K+. ### Claim 14 (depends on 1) The method of claim 1, wherein the side chains of poly (itaconic acid) are grafted to the chitosan backbone via C6 hydroxyl groups. ### Claim 15 (depends on 1) 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.