Zero valent iron systems and methods for treatment of contaminated wastewater

Patent metadata

Field	Value
Publication number	US-10329179-B2
Application number	US-201514836790-A
Country	US
Kind code	B2
Filing date	Aug 26, 2015
Priority date	Sep 18, 2009
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

Hybrid zero-valent iron systems and methods for treating a fluid containing a contaminant that removes or reduces the concentration of contaminants, such as toxic metals, metalloids, oxyanions, and dissolved silica.

First claim

The invention claimed is:

1. A method of removing or reducing the concentration of a contaminant in wastewater, comprising:
(a) contacting wastewater comprising a contaminant with a reactive solid, wherein the reactive solid comprises zero-valent iron and magnetite in contact therewith, and wherein the zero-valent iron from which the reactive solid is prepared has a particle size from about 10 μm to about 40 μm;
(b) introducing an added secondary reagent to the wastewater in contact with the reactive solid, wherein the added secondary reagent is ferrous iron.

2. The method of claim 1 further comprising adding a secondary solid to the wastewater in contact with the reactive solid, wherein the added secondary solid comprises magnetite.

3. The method of claim 2 , wherein the secondary solid comprises a plurality of particles.

4. The method of claim 1 , wherein the added secondary reagent is continuously introduced.

5. The method of claim 1 , wherein the reactive solid comprises a plurality of particles.

6. The method of claim 1 , wherein the wastewater is industrial wastewater.

7. The method of claim 1 , wherein the wastewater is flue gas desulfurization wastewater.

8. The method of claim 1 , wherein the contaminant comprises a metal, metal ion, metalloid, oxyanion, chlorinated organic compound, or a combination thereof.

9. The method of claim 1 , wherein the contaminant is selected from an arsenic, aluminum, antimony, beryllium, mercury, selenium, cobalt, lead, cadmium, chromium, silver, zinc, nickel, molybdenum, thallium, vanadium compound or an ion thereof; borates, nitrates, bromates, iodates, and periodates; trichloroethylene; dissolved silica; and combinations thereof.

10. The method of claim 1 , wherein the contaminant is selenate.

11. A method of removing or reducing the concentration of a contaminant in wastewater, comprising:
(a) treating zero-valent iron with an oxidant and ferrous iron to provide a reactive solid comprising zero-valent iron and magnetite in contact therewith, wherein the zero-valent iron has a particle size from about 10 μm to about 40 μm; and
(b) contacting wastewater comprising a contaminant with the reactive solid and an added secondary reagent, wherein the added secondary reagent is ferrous iron.

12. The method of claim 11 , wherein the oxidant is aqueous nitrate.

13. The method of claim 11 further comprising adding a secondary solid to the wastewater in contact with the reactive solid, wherein the added secondary solid comprises magnetite.

14. The method of claim 13 , wherein the secondary solid comprises a plurality of particles.

15. The method of claim 11 , wherein the added secondary reagent is continuously introduced.

16. The method of claim 11 , wherein the reactive solid comprises a plurality of particles.

17. The method of claim 11 , wherein the wastewater is industrial wastewater.

18. The method of claim 11 , wherein the wastewater is flue gas desulfurization wastewater.

19. The method of claim 11 , wherein the contaminant comprises a metal, metal ion, metalloid, oxyanion, chlorinated organic compound, or a combination thereof.

20. The method of claim 11 , wherein the contaminant is selected from an arsenic, aluminum, antimony, beryllium, mercury, selenium, cobalt, lead, cadmium, chromium, silver, zinc, nickel, molybdenum, thallium, vanadium compound or an ion thereof; borates, nitrates, bromates, iodates, and periodates; trichloroethylene; dissolved silica; and combinations thereof.

21. The method of claim 11 , wherein the contaminant is selenate.

Assignees

• Texas A & M Univ Sys

Inventors

• Huang Yongheng

Classifications

• B01J20/3085

  Chemical treatments not covered by groups B01J20/3007 - B01J20/3078 · CPC title

• C02F1/705 Primary

  Reduction by metals · CPC title

• C02F1/72

  by oxidation {(C02F1/4672 takes precedence)} · CPC title

• C02F2101/103

  Arsenic compounds · CPC title

• C02F1/281

  using inorganic sorbents · CPC title