Granted Patent B2

US 12,703,650 · App. 18/041,769 · Granted Aug 11, 2026

Inventors: William A. Tarpeh (Union City, CA); Matthew Junjie Liu (Stanford, CA); Brandon D. Clark (Attleboro, MA)

Assignee: The Board of Trustees of the Leland Stanford Junior University

C02F1/4693B01D61/461C02F1/46109C02F1/4676C05C3/00C02F2001/46142C02F2101/16C02F2101/163C02F2201/46115

Abstract

Claims (37)

1 . An apparatus for nitrogen reduction of wastewater comprising:

a first chamber comprising a salt solution and a first electrode;

a second chamber comprising a wastewater source and a second electrode;

a third chamber comprising a salt solution and a third electrode, wherein the second chamber is positioned between the first chamber and the third chamber;

an anion exchange membrane positioned between the first chamber and the second chamber; and

a cation exchange membrane positioned between the second chamber and the third chamber,

wherein the first electrode is electrically connected to a first switch, the second electrode is electrically connected to a second switch, and the third electrode is electrically connected to a third switch,

wherein each of the first switch, the second switch, and the third switch are electrically connected to a voltage source, and

wherein any two of the first switch, the second switch, or the third switch are configured to engage to create a potential bias between their corresponding chambers.

2 . The apparatus of claim 1 , further comprising an NO 3 RR electrode positioned in the first chamber.

3 . The apparatus of claim 2 , wherein the NO 3 RR electrode and the first electrode are each configured to apply a potential bias to the first chamber.

4 . The apparatus of claim 2 , wherein the NO 3 RR electrode and the first electrode are spaced apart from each other.

5 . The apparatus of claim 1 , further comprises a HER electrode positioned in the third chamber.

6 . The apparatus of claim 5 , wherein the HER electrode and the third electrode are each configured to apply a potential bias to the third chamber.

7 . The apparatus of claim 5 , wherein the HER electrode and the third electrode are spaced apart from each other.

8 . The apparatus of claim 1 , wherein the first switch, the second switch, and third switch are electrically connected to a voltage source.

9 . The apparatus of claim 8 , wherein the voltage source is reversable.

10 . The apparatus of claim 1 , wherein the first electrode and/or the second electrode comprises a metal oxide mesh material.

11 . The apparatus of claim 10 , wherein the metal oxide mesh material comprises TiO 2 , IrO 2 and/or Ta 2 O 5 .

12 . The apparatus of claim 1 , wherein the third electrode comprises stainless steel.

13 . A method of nitrogen reduction of wastewater, the method comprising:

providing an apparatus comprising:

a first chamber comprising a salt solution and a first electrode;

a second chamber comprising a wastewater source and a second electrode;

a third chamber comprising a salt solution and a third electrode, wherein the second chamber is positioned between the first chamber and the third chamber;

an anion exchange membrane positioned between the first chamber and the second chamber; and

a cation exchange membrane positioned between the second chamber and the third chamber;

wherein the first electrode is electrically connected to a first switch, the second electrode is electrically connected to a second switch, and the third electrode is electrically connected to a third switch, and

wherein each of the first switch, the second switch, and the third switch are electrically connected to a voltage source;

applying a potential bias between any two of the first switch, the second switch, and the third switch and their corresponding chambers.

14 . The method of claim 13 , further comprising performing electrodialysis by applying an ionizing potential bias with a negative polarity to the third chamber and a positive polarity to the first chamber.

15 . The method of claim 14 , further comprising performing nitrate reduction by applying an ionizing potential bias with a negative polarity to the first chamber and a positive polarity to the second chamber.

16 . The method of claim 15 , further comprising performing product purification by applying an ionizing potential bias with a negative polarity to the second chamber and a positive polarity to the third chamber.

17 . The method of claim 13 , further comprising performing disinfectant production by applying an ionizing potential bias with a negative polarity to the third chamber and a positive polarity to the second chamber.

18 . The method of claim 17 , further comprising performing anion migration by applying an ionizing potential bias with a negative polarity to the second chamber and a positive polarity to the first chamber.

19 . The method of claim 18 , further comprising performing nitrate reduction by applying an ionizing potential bias with a negative polarity to the first chamber and a positive polarity to the second chamber.

20 . The method of claim 19 , further comprising performing fertilizer production by applying an ionizing potential bias with a negative polarity to the second chamber and a positive polarity to the first chamber.

Assignments (1)

Continuity (2)

References Cited (116)