Target species recovery and related systems and methods

Patent metadata

Field	Value
Publication number	US-2022119283-A1
Application number	US-201917272007-A
Country	US
Kind code	A1
Filing date	Aug 28, 2019
Priority date	Aug 28, 2018
Publication date	Apr 21, 2022
Grant date	—

Abstract

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

First claim

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.

2 . The method of claim 1 , further comprising:
releasing the target species from the first electrode such that, after the release, the heavy metal, transition metal, and/or 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.

3 . 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 is adsorbed on the first electrode; 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.

4 . The method of claim 1 , wherein the target species comprises As, Sb, Tc, Cr, Mo, W, and/or V.

5 . The method of claim 1 , wherein the target species comprises As, Cr, and/or V.

6 . The method of claim 1 , further comprising contacting the first electrode with a fluid source comprising the target species.

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

8 . The method of claim 1 , 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.

9 . The method of claim 1 , further comprising electrochemically transforming the target species by reduction or oxidation.

10 . The method of claim 1 , wherein the target species comprises any ionic variation of hexavalent chromium (VI).

11 . The method of claim 10 , wherein the hexavalent chromium (VI) is present as Cr 2 O 7 2− , CrO 4 2− , and/or HCrO 4 − .

12 . The method of claim 1 , 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).

13 . The method of claim 1 , further comprising splitting water at the second electrode.

14 . The method of claim 1 , wherein the electrical potential is less than 1.2 V vs. a standard hydrogen electrode.

15 . The method of claim 1 , further comprising altering the pH of a 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.

16 . The method of claim 15 , wherein the first pH value is different from the second pH value by at least 0.5 pH units.

17 . The method of claim 15 , wherein the first pH value is higher than the second pH value.

18 . An electrochemical system comprising:
a first electrode comprising a first conductive substrate and a first redox species immobilized to the first conductive substrate, wherein the first redox species is selective toward a target species; and a second electrode; wherein the target species comprises a heavy metal, a transition metal, and/or a metalloid.

19 . The electrochemical system of claim 18 , wherein the target species comprises As, Sb, Tc, Cr, Mo, W, and/or V.

20 . The electrochemical system of claim 18 , wherein the target species comprises As, Cr, and/or V.

21 - 28 . (canceled)

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

• C02F1/469 Primary

  by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis · CPC title