Target species recovery and related systems and methods

Patent metadata

Field	Value
Publication number	US-12454472-B2
Application number	US-201917272007-A
Country	US
Kind code	B2
Filing date	Aug 28, 2019
Priority date	Aug 28, 2018
Publication date	Oct 28, 2025
Grant date	Oct 28, 2025

Abstract

The recovery of target species, and related systems and methods, are generally described.

First claim

What is claimed is:

1. A method, comprising:
applying an electrical potential across a first electrode comprising a first conductive substrate and a first redox species immobilized to the first conductive substrate and a second electrode, such that a target species comprising a heavy metal, a transition metal, and/or a metalloid is adsorbed on the first electrode based on a specific chemical interaction between the first redox species and the target species;
splitting water at the second electrode;
electrochemically transforming the target species by reduction; and
releasing the target species from the first electrode such that, after the release, the heavy metal, the transition metal, and/or the metalloid has an oxidation state that is different from the oxidation state of the heavy metal, transition metal, and/or metalloid just prior to the adsorption of the target species on the first electrode,
wherein splitting the water at the second electrode comprises generating protons and lowering a pH of a fluid in contact with the first electrode, and wherein electrochemically transforming the target species by reduction comprises reducing the target species using the protons as a co-reagent.

2. A method, comprising:
applying an electrical potential across a first electrode comprising a first conductive substrate and a first redox species immobilized to the first conductive substrate and a second electrode, such that a target species comprising a heavy metal, a transition metal, and/or a metalloid is adsorbed on the first electrode;
splitting water at the second electrode;
electrochemically transforming the target species by reduction; and
releasing the target species from the first electrode such that, after the release, an atom of the target species has an oxidation state that is different from the oxidation state of that atom just prior to the adsorption of the target species on the first electrode,
wherein splitting the water at the second electrode comprises generating protons and lowering a pH of a fluid in contact with the first electrode, and wherein electrochemically transforming the target species by reduction comprises reducing the target species using the protons as a co-reagent.

3. The method of claim 2 , wherein the target species comprises As, Sb, Tc, Cr, Mo, W, and/or V.

4. The method of claim 2 , wherein the target species comprises As, Cr, and/or V.

5. The method of claim 2 , further comprising contacting the first electrode with the fluid, wherein the fluid comprises the target species.

6. The method of claim 5 , wherein the target species is at a concentration of between or equal to 10,000 ppb and 100 ppb in the fluid prior to applying the electrical potential.

7. The method of claim 2 , wherein releasing the target species comprises applying a second electrical potential to the first electrode such that the target species is released from the first electrode.

8. The method of claim 2 , wherein the target species comprises any ionic variation of hexavalent chromium (VI).

9. The method of claim 8 , wherein the hexavalent chromium (VI) is present as Cr 2 O 7 2− , CrO 4 2− , and/or HCrO 4 − .

10. The method of claim 2 , wherein the target species comprises Cr(VI) just prior to its adsorption on the first electrode, and, after the target species has been released from the first electrode, the target species comprises Cr(III).

11. The method of claim 2 , wherein the electrical potential is less than 1.2 V vs. a standard hydrogen electrode.

12. The method of claim 2 , further comprising altering the pH of the fluid in contact with the first electrode, such that the fluid has a first pH value prior to the adsorption of the target species on the first electrode and the fluid has a second pH value after the release of the target species.

13. The method of claim 12 , wherein the first pH value is different from the second pH value by at least 0.5 pH units.

14. The method of claim 12 , wherein the first pH value is higher than the second pH value.

15. The method of claim 2 , wherein electrochemically transforming the target species by reduction comprises electrochemically transforming the heavy metal, the transition metal, and/or the metalloid from a positive oxidation state to a lower positive oxidation state.

16. A method, comprising:
applying an electrical potential across a first electrode comprising a first conductive substrate and a first redox species immobilized to the first conductive substrate and a second electrode, such that a target species comprising a heavy metal, a transition metal, and/or a metalloid is adsorbed on the first electrode, wherein the first redox species comprises an organometallic compound comprising at least one metal-carbon bond;
splitting water at the second electrode;
electrochemically transforming the heavy metal, the transition metal, and/or the metalloid from a positive oxidation state to a lower positive oxidation state; and
releasing the target species from the first electrode,
wherein splitting the water at the second electrode comprises generating protons and lowering a pH of a fluid in contact with the first electrode, and wherein electrochemically transforming the heavy metal, the transition metal, and/or the metalloid from a positive oxidation state to a lower positive oxidation state comprises reducing the heavy metal, the transition metal, and/or the metalloid using the protons as a co-reagent.

17. The method of claim 16 , wherein the first redox species comprises a metallocene.

18. The method of claim 16 , wherein the first redox species comprises polyvinyl(ferrocene).

Assignees

• Massachusetts Inst Technology

Inventors

• Hatton Trevor Alan
• Su Xiao
• Halliday Cameron G

Classifications

• C02F2209/06

  pH · CPC title

• C02F2101/006

  Radioactive compounds · CPC title

• C02F2101/10

  Inorganic compounds · CPC title

• C02F1/4691

  Capacitive deionisation · CPC title

• C02F2101/20

  Heavy metals or heavy metal compounds · CPC title