Detection and removal of selenate from aqueous solution

Patent metadata

Field	Value
Publication number	US-2018057371-A1
Application number	US-201715689049-A
Country	US
Kind code	A1
Filing date	Aug 29, 2017
Priority date	Aug 29, 2016
Publication date	Mar 1, 2018
Grant date	—

Abstract

Systems and methods for detecting and/or removing selenate from an aqueous selenate-containing solution are described. The method includes adding sufficient acid to the aqueous selenate-containing solution to acidify the aqueous selenate-containing solution; contacting the acidic aqueous selenate-containing solution with an underpotantial deposited copper-coated electrode; and removing selenate from the aqueous selenate-containing solution by forming copper-selenide on the underpotential copper-coated electrode.

First claim

What is claimed is:

1 . A method for removing selenate from an aqueous selenate-containing solution, comprising the steps of:
adding sufficient acid to the aqueous selenate-containing solution to acidify the aqueous selenate-containing solution; contacting the acidic aqueous selenate-containing solution with an underpotential copper-coated electrode; and removing selenate from the aqueous selenate-containing solution by forming copper-selenide on the underpotential copper-coated electrode.

2 . The method of claim 1 , wherein the underpotential copper-coated electrode is formed by contacting an electrode with an acidic copper-containing aqueous solution and applying sufficient potential to the electrode to form an underpotential copper-coated electrode.

3 . The method of claim 2 , wherein the copper-containing aqueous solution is formed by contacting an acidic aqueous selenate-containing solution with a copper (II) salt.

4 . The method of claim 2 , wherein the potential of the electrode is from about 0.55 to 0.33 V RHE during formation of the underpotential copper-coated electrode.

5 . The method of claim 1 , wherein the electrode is a gold electrode.

6 . The method of claim 1 , further comprising the step of regenerating the electrode.

7 . The method of claim 6 , wherein the electrode is regenerated by removing copper from the copper-selenide-coated electrode, and then releasing selenium from the electrode by applying a positive voltage to the electrode.

8 . The method of claim 1 , wherein the acidic aqueous selenate-containing solution has a pH from about 0.8 to about 1.5.

9 . The method of claim 1 , wherein the acid is HClO 4 .

10 . The method of claim 1 , wherein the aqueous selenate-containing solution also comprises selenite, and the method also removes selenite from the aqueous selenate-containing solution.

11 . A method for detecting selenate in an aqueous solution, comprising the steps of:
adding sufficient acid to the aqueous solution to acidify the aqueous solution; contacting the acidic aqueous solution with an underpotential copper-coated electrode; and scanning the potential of the electrode above 1.0 V vs. RHE to determine if it is coated with copper selenide.

12 . The method of claim 11 , wherein the electrode is a gold electrode.

13 . The method of claim 11 , wherein the underpotential copper-coated electrode is formed by contacting an electrode with an acidic copper-containing aqueous solution and applying sufficient potential to the electrode to form an underpotential copper-coated electrode.

14 . The method of claim 13 , wherein the copper-containing aqueous solution is formed by contacting an acidic aqueous selenate-containing solution with a copper (II) salt.

15 . The method of claim 13 , wherein the potential of the electrode is from about 0.55 to 0.33 V RHE during formation of the underpotential copper-coated electrode.

16 . The method of claim 11 , wherein the acidic aqueous solution has a pH from about 0.8 to about 1.5.

17 . The method of claim 11 , wherein the acid is HClO 4 .

18 . The method of claim 11 , wherein the aqueous solution is drinking water.

19 . A system for detecting or removing selenate from an aqueous solution, comprising:
a first container holding an acidic aqueous solution including selenate; an underpotential copper-coated electrode positioned in contact with the acidic aqueous solution including selenate; a counter electrode positioned in contact with the acidic aqueous solution including selenate; a RHE electrode positioned in contact with the acidic aqueous solution including selenate, and a voltage source connected to and capable of applying a voltage to the underpotential copper-coated electrode, wherein application of voltage to the copper-coated electrode converts the electrode to a copper-selenide-coated electrode.

20 . The system of claim 19 , wherein the underpotential copper-coated electrode is a gold electrode.

21 . The system of claim 19 , wherein the system further comprises a second container holding an aqueous solution for receiving selenite from the copper-selenide-coated electrode.

22 . The system of claim 19 , wherein the acidic aqueous solution has a pH from about 0.8 to about 1.5.

Assignees

• Univ Case Western Reserve

Inventors

• Scherson Daniel A
• Strobl Jonathan

Classifications

• C25B11/057

  consisting of a single element or compound · CPC title

• C02F2101/106

  Selenium compounds · CPC title

• C01B19/008

  Salts of oxyacids of selenium or tellurium · CPC title

• C25B11/0447

  Chemistry & Metallurgy · mapped topic

• C02F1/58

  by removing specified dissolved compounds (using ion-exchange C02F1/42; softening water C02F5/00) · CPC title