Contaminate removal using aluminum-doped magnetic nanoparticles

Patent metadata

Field	Value
Publication number	US-11639301-B2
Application number	US-202016789698-A
Country	US
Kind code	B2
Filing date	Feb 13, 2020
Priority date	Jun 3, 2016
Publication date	May 2, 2023
Grant date	May 2, 2023

Abstract

Exemplary embodiments of the present invention can include a method for isolating a contaminate from water comprising: introducing a plurality of aluminum-doped nanoparticles to water, the water comprising the contaminate; contacting the plurality of aluminum-doped nanoparticles with the contaminate to form contaminate-adsorbed nanoparticles; and isolating the contaminate-adsorbed nanoparticles by applying a magnetic field to the water.

First claim

I claim:

1. A method comprising:
dispersing solid solution aluminum-doped magnetite nanoparticles in a fluid having a contaminate, forming contaminate-adsorbed nanoparticles;
applying a magnetic field to the fluid, which segregates at least a portion of the contaminate-adsorbed nanoparticles;
applying a magnetic field to the fluid, which segregates at least a portion of the contaminate-adsorbed nanoparticles;
removing at least a portion of the segregated contaminate-adsorbed nanoparticles from the fluid; and
regenerating with an aluminum solution at least a portion of the removed contaminate-adsorbed nanoparticles into regenerated solid solution aluminum-doped magnetite nanoparticles;
wherein the solid solution aluminum-doped magnetite nanoparticles prior to regenerating have an initial contaminate removal efficacy; and
wherein the regenerated solid solution aluminum-doped magnetite nanoparticles have a regenerated contaminate removal efficacy that is at least 70% of the initial contaminate removal efficacy.

2. The method of claim 1 , wherein the solid solution aluminum-doped magnetite nanoparticles have a single crystal structure.

3. The method of claim 1 , wherein the solid solution aluminum-doped magnetite nanoparticles are characterized by a maximum contaminate adsorption capacity of greater than 50 mg/g based on the Langmuir model.

4. The method of claim 1 , wherein the contaminate is selected from the group consisting of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), fat-oil-grease (FOG), total Kjeldahl nitrogen (TKN), suspended solids, dissolved solids, and a combination thereof;
wherein the solid solution aluminum-doped magnetite nanoparticles are synthesized from a mixture of ferric salt, ferrous salt, and aluminum salt with a basic solution including one or both sodium hydroxide and ammonium hydroxide; and
wherein the solid solution aluminum-doped magnetite nanoparticles are characterized by a maximum contaminate adsorption capacity of greater than 50 mg/g based on the Langmuir model.

5. The method of claim 1 , wherein the solid solution aluminum-doped magnetite nanoparticles are synthesized from a mixture of ferric salt, ferrous salt, and aluminum salt with a basic solution including one or both sodium hydroxide and ammonium hydroxide.

6. The method of claim 1 , wherein an isolation efficiency of the contaminate-adsorbed nanoparticles is pH-independent in the range of the fluid pH from 4 to 9.

7. The method of claim 1 , wherein the solid solution aluminum-doped magnetite nanoparticles are characterized by a maximum contaminate adsorption capacity of greater than 81 mg/g based on the Langmuir model.

8. The method of claim 1 , wherein the solid solution aluminum-doped magnetite nanoparticles are characterized by a maximum contaminate adsorption capacity of greater than 102 mg/g based on the Langmuir model.

9. The method of claim 1 , wherein a containment concentration of the fluid after removal of at least a portion of the removed contaminate-adsorbed nanoparticles is from about 40% to about 97% less than a containment concentration of the fluid prior to forming the contaminate-adsorbed nanoparticles.

10. The method of claim 2 , wherein the solid solution aluminum-doped magnetite nanoparticles are produced by the process comprising:
dissolving stoichiometric amounts of ferric salt, ferrous salt, and aluminum salt in a fluid to form a solution; and
increasing the pH of the solution using a basic solution including one or both sodium hydroxide and ammonium hydroxide until precipitation of the solid solution aluminum-doped magnetite nanoparticles.

11. The method of claim 10 , wherein the process of producing the solid solution aluminum-doped magnetite nanoparticles further comprises:
heating the solution prior to increasing the pH of the solution; and
heating the solution during increasing the pH of the solution.

12. The method of claim 10 , wherein the ferric salt, ferrous salt, and aluminum salt comprise Al 2 (SO 4 ) 3 , FeCl 3 , and FeCl 2 ;
wherein increasing the pH of the solution comprises increasing the pH of the solution with the addition of one or both of NaOH and NH 4 OH; and
wherein the solid solution aluminum-doped magnetite nanoparticles comprise 20 to 50% aluminum.

13. A method comprising:
forming contaminate-adsorbed nanoparticles by introducing solid solution aluminum-doped magnetite nanoparticles having a magnetite structure with aluminum fully incorporated in the cubic inverse spinel lattice of the magnetite structure to a fluid with a contaminate selected from the group consisting of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), fat-oil-grease (FOG), total Kjeldahl nitrogen (TKN), suspended solids, dissolved solids, and a combination thereof;
isolating at least a portion of the contaminate-adsorbed nanoparticles by applying a magnetic field to the fluid;
removing at least a portion of the isolated contaminate-adsorbed nanoparticles from the fluid; and
regenerating with an aluminum solution at least a portion of the removed contaminate-adsorbed nanoparticles into regenerated solid solution aluminum-doped magnetite nanoparticles;
wherein the solid solution aluminum-doped magnetite nanoparticles are characterized by a maximum contaminate adsorption capacity of greater than 50 mg/g based on the Langmuir model;
wherein the solid solution aluminum-doped magnetite nanoparticles prior to regenerating have an initial contaminate removal efficacy; and
wherein the regenerated solid solution aluminum-doped magnetite nanoparticles are configured such that after the same solid solution aluminum-doped magnetite nanoparticles have been regenerated up through 11 cycles of being regenerated, the cycled regenerated solid solution aluminum-doped magnetite nanoparticles have a regenerated contaminate removal efficacy that is at least 70% of the initial contaminate removal efficacy.

14. The method of claim 13 , wherein an isolation efficiency of the contaminate-adsorbed nanoparticles is pH-independent in the range of the fluid pH from 4 to 9.

15. The method of claim 13 , wherein the solid solution aluminum-doped magnetite nanoparticles are synthesized from a mixture of ferric salt, ferrous salt, and aluminum salt with sodium hydroxide; and
wherein the solid solution aluminum-doped magnetite nanoparticles are characterized by a maximum contaminate adsorption capacity of greater than 81 mg/g based on the Langmuir model.

16. The method of claim 13 , wherein the solid solution aluminum-doped magnetite nanoparticles are characterized by a maximum contaminate adsorption capacity of greater than 102 mg/g based on the Langmuir model.

17. The method of claim 13 , wherein a containment concentration of the fluid after removal of at least a portion of the isolated contaminate-adsorbed nanoparticles is from about 40% to about 97% less than a containment concentration of the fluid prior to forming the contaminate-adsorbed nanoparticles.

18. The method of claim 13 , wherein the solid solution aluminum-doped magnetite nanoparticles are produced by the process comprising:
dissolving stoichiometric amounts of ferric salt, ferrous salt, and aluminum salt in a fluid to form a solution; and
increasing the pH of the solution using a basic solution including one or both sodium hydroxide and ammonium hydroxide until precipitation of the solid solution aluminum-doped magnetite nanoparticles.

Assignees

• Georgia Tech Res Inst

Inventors

• Xu Jie

Classifications

• C02F2103/22

  from the processing of animals, e.g. poultry, fish, or parts thereof · CPC title

• C02F2305/08

  Nanoparticles or nanotubes · CPC title

• C02F1/488 Primary

  for separation of magnetic materials, e.g. magnetic flocculation · CPC title

• B01D15/02

  with moving adsorbents · CPC title

• B01D15/3885

  using electrical or magnetic means · CPC title