# US 12,179,174 B2 · Method for preparing an iron oxide particle core composite

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- Number: US 12,179,174 B2
- Document ID: US12179174B2
- Status: Granted
- Kind: B2
- Application number: 17/745,934
- Filed: 2022-05-17
- Published: 2022-09-22
- Granted: 2024-12-31
- Earliest claimed: 2019-07-23
- Assignees: King Fahd University of Petroleum and Minerals
- Applicants: King Fahd University of Petroleum and Minerals
- Inventors: Tawfik Abdo Saleh Awadh; Akram Abdulhakeem Al-Absi
- Web page: https://patentgrep.com/patent/US12179174B2

## CPC

- B01J 20/28009: {Magnetic properties}
- B01J 20/06: comprising oxides or hydroxides of metals not provided for in group B01J20/04
- B01J 20/20: comprising free carbon; comprising carbon obtained by carbonising processes
- B01J 20/262: {obtained otherwise than by reactions only involving carbon to carbon unsaturated bonds, e.g. obtained by polycondensation (macromolecular compounds obtained otherwise than by reactions only involving unsaturated carbon-to-carbon bonds per se C08G)}
- B01J 20/28061: {being in the range 100-500 m2/g}
- B01J 20/28071: {being less than 0.5 ml/g}
- B01J 20/28083: {being in the range 2-50 nm, i.e. mesopores}
- B01J 20/3085: {Chemical treatments not covered by groups B01J20/3007 - B01J20/3078}
- C01B 32/324: from waste materials, e.g. tyres or spent sulfite pulp liquor
- C01B 32/336: characterised by gaseous activating agents
- C02F 1/288: {using composite sorbents, e.g. coated, impregnated, multi-layered}
- C08G 83/001: {Macromolecular compounds containing organic and inorganic sequences, e.g. organic polymers grafted onto silica}
- B01J 2220/46: Materials comprising a mixture of inorganic and organic materials (materials coated or impregnated on a carrier B01J20/32)
- B01J 2220/4806: the starting material being of inorganic character
- C01B 32/354: After-treatment
- C02F 1/281: {using inorganic sorbents}
- C02F 1/283: {using coal, charred products, or inorganic mixtures containing them}
- C02F 2101/20: Heavy metals or heavy metal compounds
- C02F 2101/22: Chromium or chromium compounds, e.g. chromates
- C02F 2101/308: {Dyes; Colorants; Fluorescent agents}
- C02F 2305/08: Nanoparticles or nanotubes
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- 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)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

A polymer/activated carbon composite made up of a branched polyethylenimine and magnetic cores involving Fe3O4 disposed activated carbon. The magnetic cores have activated carbonyl groups on the surface. A process for removing organic dyes, such as methyl red, as well as heavy metal ions from a polluted aqueous solution or an industrial wastewater utilizing the composite is introduced. A method of synthesizing the polymer/activated carbon composites is also specified.

## Claims

### Claim 1

A method of preparing a composite, comprising:
treating an activated carbon with an acid to form a carboxylated carbon, wherein the acid is selected from the group consisting of HNO3, H2SO4, H3PO4 and HClO4;
mixing the carboxylated carbon, a Fe(II) salt, a Fe(III) salt, and a base in the presence of a solvent to form a mixture;
heating the mixture to form a magnetic carbon;
mixing the magnetic carbon and a halide reagent to form a magnetic core; and
reacting the magnetic core with a branched polyethylenimine thereby forming the composite,
wherein the halide reagent is at least one selected from the group consisting of a thionyl halide, an oxalyl halide, phosphorus trihalide, and phosphorous pentahalide,
wherein the magnetic core comprises Fe3O4 disposed on the activated carbon and the branched polyethylenimine,
wherein the Fe3O4 is in the form of nanoparticles having an average particle size of 1-100 nm; and
wherein the magnetic core comprises acyl halide groups on a surface of the magnetic core.

### Claim 2 (depends on 1)

The method of claim 1, wherein the activated carbon is formed by granulating and pyrolyzing waste tires.

### Claim 3 (depends on 1)

The method of claim 1, wherein the Fe(II) salt is FeSO4, and wherein the Fe(III) salt is FeCl3.

### Claim 4 (depends on 1)

The method of claim 1, wherein the acid is nitric acid, and wherein the base is sodium hydroxide, ammonium hydroxide, or both.

### Claim 5 (depends on 1)

The method of claim 1, wherein the mixture has a pH in a range of 8-14.

### Claim 6 (depends on 1)

The method of claim 1, wherein the heating is performed at a temperature of 70-150° C. for 2-12 hours.

### Claim 7 (depends on 1)

The method of claim 1, wherein the reacting is performed at a temperature of 30-100° C. for 4-24 hours.

### Claim 8 (depends on 1)

The method of claim 1, wherein the branched polyethylenimine is bonded to the surface of the magnetic core via an amide linkage.

### Claim 9 (depends on 1)

The method of claim 1, wherein the branched polyethylenimine has a number average molecular weight in a range of 200-80,000 Da.

### Claim 10 (depends on 1)

The method of claim 1, wherein a weight ratio of the Fe3O4 nanoparticles to the activated carbon in the composite is in a range of 2:3 to 3:1.

### Claim 11 (depends on 1)

The method of claim 1, wherein the composite has a surface area of 140-180 m2/g.

### Claim 12 (depends on 1)

The method of claim 1, wherein the composite has a pore volume of 0.2-0.28 cm3/g, and a pore size of 4-8 nm.