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JP-2026074590-A - Electrolytic devices

JP2026074590AJP 2026074590 AJP2026074590 AJP 2026074590AJP-2026074590-A

Abstract

[Problem] To provide an electrolytic device capable of improving the current efficiency of a desired electrodialysis reaction. [Solution] The electrolytic device according to this embodiment comprises a cathode electrode 28 containing a cathode catalyst that generates H2 and hydroxide ions by electrolytic reduction of H2O , a first chamber 30 in which the cathode electrode 28 is placed and an aqueous medium is supplied, a second chamber 26 in which an electrolyte containing alkali metal ions is supplied, and a second cation exchange membrane 34 disposed between the first chamber 30 and the second chamber 26, wherein when a voltage is applied to the cathode electrode 28, an alkali hydroxide aqueous solution is generated in the first chamber 30 by a reaction between the alkali metal ions supplied from the second chamber 26 through the second cation exchange membrane 34 and the hydroxide ions generated at the cathode electrode 28, and the average linear velocity ( u1 ) of the aqueous medium in the first chamber 30 when the voltage is applied is greater than the average linear velocity ( u2 ) of the electrolyte in the second chamber 26. [Selection Diagram] Figure 1

Inventors

  • 西村 友作
  • 猪飼 正道
  • 加藤 千和
  • 岡村 和政

Assignees

  • 株式会社豊田中央研究所
  • トヨタ自動車株式会社

Dates

Publication Date
20260507
Application Date
20241021

Claims (7)

  1. A cathode electrode containing a cathode catalyst, which generates H₂ and hydroxide ions by electrolytic reduction of H₂O , The cathode electrode is placed in a first chamber to which an aqueous medium is supplied, A second chamber is supplied with an electrolyte containing alkali metal ions, The device comprises a cation exchange membrane disposed between the first chamber and the second chamber, When a voltage is applied to the cathode electrode, an alkali hydroxide aqueous solution is produced in the first chamber by a reaction between the alkali metal ions supplied from the second chamber through the cation exchange membrane and the hydroxide ions generated at the cathode electrode. An electrolytic device characterized in that the average linear velocity ( u1 ) of the aqueous medium in the first chamber when the voltage is applied is greater than the average linear velocity ( u2 ) of the electrolyte in the second chamber.
  2. The electrolytic device according to claim 1, characterized in that the operating current density (J) of the cathode electrode satisfies J [A/ cm² ] > 0.02 A/ cm² , and the average linear velocity ( u1 ) of the aqueous medium satisfies u1 [cm/min] ≥ 77 cm/min × C (where C is a solubility correction coefficient).
  3. The electrolytic device according to claim 2, characterized in that the average flow rate ( V1 ) of the aqueous medium in the first chamber satisfies V1 [ cm³ /min] ≥ 5cm³ /min × C (where C is a solubility correction coefficient).
  4. The electrolytic device according to claim 1, characterized in that the operating current density (J) of the cathode electrode satisfies 0 A/ cm² < J [A/ cm² ] ≤ 0.02 A/ cm² , and the average linear velocity ( u1 ) of the aqueous medium satisfies u1 [cm/min] ≥ 3850 [ cm³ /A・min] × C × J [A/ cm² ] (where C is a solubility correction coefficient).
  5. The electrolytic device according to any one of claims 1 to 4, characterized in that the average flow rate ( V1 ) of the aqueous medium in the first chamber is greater than the average flow rate ( V2 ) of the electrolyte in the second chamber.
  6. The electrolytic device according to any one of claims 1 to 4 , characterized in that the ratio ( u1 / u2 ) of the average linear velocity of the aqueous medium in the first chamber to the average linear velocity of the electrolyte in the second chamber (u2) is 5 or more.
  7. The electrolytic device according to any one of claims 1 to 4, characterized in that the ratio ( V1 / V2 ) of the average flow rate of the aqueous medium in the first chamber to the average flow rate of the electrolyte in the second chamber ( V2 ) is 5 or more.

Description

This invention relates to the technology of electrolytic devices. As technologies that can contribute to carbon neutralization, there is interest in electrolytic devices that utilize electrolysis technology to obtain CO2 reduction valuable products from carbonate ion species or carbon dioxide, and electrodialysis technology that recovers carbon dioxide using an alkaline aqueous solution containing carbonate ion species ( at least one of carbonate ions ( CO3 2- ) and bicarbonate ions ( HCO3- )), and separates and concentrates carbon dioxide from the recovered solution containing carbon dioxide. For example, Patent Documents 1-6 and Non-Patent Document 1 disclose an electrodialysis apparatus that separates and concentrates carbon dioxide by applying voltage to the anode and cathode electrodes. Furthermore, Patent Documents 7-12 and Non-Patent Documents 2-3 disclose a technique for separating and recovering an aqueous lithium hydroxide solution from the acid treatment solution of a positive electrode active material used in a lithium-ion battery, although this technique is not for the purpose of separating and concentrating carbon dioxide. Patent Documents 13-14 also disclose a technique for removing sparingly soluble salts and ions that segregate during electrodialysis. Patent Publication No. 5848964Japanese Patent Publication No. 2012-096975Patent Publication No. 5750220Japanese Patent Publication No. 2008-100211International Publication No. 2022/235708Patent Publication No. 5952104Japanese Patent Publication No. 2012-234732Patent Publication No. 7143466Patent Publication No. 6864739Japanese Patent Publication No. 2014-173144Patent Publication No. 7101995International Publication No. 2024/014540Japanese Patent Publication No. 2020-028872Patent Publication No. 3416455 A. Iizuka et al., “Carbon dioxide recovery from carbonate solutions using bipolar membrane electrodialysis”, Separation and Purification Technology, 101, 49(2012)K. H. Chan, M. Malik, and G. Azimi, “Separation of lithium, nickel, manganese, and cobalt from waste lithium-ion batteries using electrodialysis”, Resour. Conserv. Recycl., 178, 106076(2022)J. -M. A. Juve, F. M. S. Christensen, Y. Wang, and Z. Wei, “Electrodialysis for metal removal and recovery: A review”, Chem. Eng. J., 435, 134857(2022) This is a schematic diagram showing an example of an electrolytic system according to this embodiment.This is a schematic diagram showing another example of the electrolytic device of this embodiment.This is a schematic diagram showing another example of the electrolytic device of this embodiment.This figure illustrates preferred conditions for the average linear velocity u1 of an aqueous medium to improve current efficiency in a desired electrodialysis reaction.(a) is a diagram showing the relationship between current efficiency and dialysis progress indicators in Experimental Example 2-1, (b) is a diagram showing the relationship between current efficiency and dialysis progress indicators in Experimental Example 2-2, and (c) is a diagram showing the relationship between current efficiency and dialysis progress indicators in Experimental Example 2-3.This figure shows the relationship between the current efficiency and the average flow rate of the aqueous medium in the first chamber in Experimental Example 3. Embodiments of the present invention will be described below. This embodiment is an example of implementing the present invention, and the present invention is not limited to this embodiment. Figure 1 is a schematic diagram showing an example of an electrolytic system according to this embodiment. The electrolytic system 1 shown in Figure 1 comprises an electrolytic device 10, a gas-liquid separation device 12, an H2 supply mechanism 14, an aqueous medium supply device 15, and an electrolyte supply device 17. The electrolytic device 10 shown in Figure 1 includes an anode electrode 22, a third chamber 24, a second chamber 26, a cathode electrode 28, a first chamber 30, a first cation exchange membrane 32, a second cation exchange membrane 34, and frame members 36a and 36b. The third chamber 24 is provided between the frame member 36a and the first cation exchange membrane 32, and the anode electrode 22 is located there. The anode electrode 22 is adjacent to the first cation exchange membrane 32. In the third chamber 24, the space between the anode electrode 22 and the frame member 36a is a flow path 23 through which a gas containing H2 flows. The first chamber 30 is provided between the frame member 36b and the second cation exchange membrane 34, and the cathode electrode 28 is located there. The cathode electrode 28 is adjacent to the second cation exchange membrane 34. In the first chamber 30, the space between the cathode electrode 28 and the frame member 36b is a flow path 29 through which an aqueous medium flows. The second chamber 26 is located between the first cation exchange membrane 32 and the second cation exchange membrane 34. Specific