Method for preparing hydrogen sulfide from sulfur dioxide by electrochemical reduction

Patent metadata

Field	Value
Publication number	US-2022316078-A1
Application number	US-202217707903-A
Country	US
Kind code	A1
Filing date	Mar 29, 2022
Priority date	Mar 31, 2021
Publication date	Oct 6, 2022
Grant date	—

Abstract

A method for preparing hydrogen sulfide from sulfur dioxide by electrochemical reduction includes electrochemically reducing sulfur dioxide absorbed in an aqueous solution into gaseous hydrogen sulfide with a membrane electrode, resulting in efficient and selective conversion of the sulfur dioxide absorbed in the aqueous solution into the hydrogen sulfide to avoid a deactivation of a cathode due to colloidal sulfur produced on the cathode and adhesion onto a surface of the cathode, wherein the method is carried out at ambient temperature and normal pressure without addition of a reducing agent, having no waste salts produced, and is simple in operation, and is convenient for large-scale application.

First claim

What is claimed is:

1 . A method for preparing hydrogen sulfide from sulfur dioxide by an electrochemical reduction, comprising electrochemically reducing the sulfur dioxide absorbed in an aqueous solution into gaseous hydrogen sulfide with a membrane electrode, wherein the membrane electrode is a porous membrane with a catalytic function.

2 . The method according to claim 1 , wherein the porous membrane with the catalytic function is composed of a porous hydrophobic membrane substrate and at least one of elemental metal, metal sulfide, and metal selenide as catalytic materials supported on a surface of the porous hydrophobic membrane substrate, or the porous membrane with the catalytic function is composed of a material with the catalytic function and a surface hydrophobic function.

3 . The method according to claim 2 , wherein
the porous hydrophobic membrane substrate is composed of a porous hydrophobic material, or is composed of a porous material with a surface hydrophobic treatment; the elemental metal is at least one selected from the group consisting of lead, copper, cobalt, iron, nickel, gold, silver, platinum, and palladium; the metal sulfide is at least one selected from the group consisting of lead sulfide, copper sulfide, cobalt sulfide, iron sulfide, nickel sulfide, gold sulfide, silver sulfide, platinum sulfide, and palladium sulfide; and the metal selenide is at least one selected from the group consisting of lead selenide, copper selenide, cobalt selenide, iron selenide, nickel selenide, gold selenide, silver selenide, platinum selenide, and palladium selenide.

4 . The method according to claim 3 , wherein
the porous hydrophobic material is at least one selected from the group consisting of PTFE, PEEK, PP, PE, a carbon cloth, and a porous carbon paper; and the porous material with the surface hydrophobic treatment is a porous material with a surface modified by hydrophobic macromolecules or hydrophobic micromolecules, or is a porous material with a hydrophobic surface processed in a micro-nano scale.

5 . The method according to claim 2 , wherein the material with the catalytic function and the surface hydrophobic function is a carbon cloth, a porous carbon paper, or a porous metal material with a surface hydrophobic treatment.

6 . The method according to claim 1 , wherein the electrochemical reduction of the sulfur dioxide absorbed in the aqueous solution is carried out by using a three-electrode system with the aqueous solution absorbed with the sulfur dioxide as a cathode compartment electrolyte and the membrane electrode as a working electrode.

7 . The method according to claim 1 , wherein the aqueous solution absorbed with the sulfur dioxide is obtained by absorbing the sulfur dioxide into lye or water, or the aqueous solution absorbed with the sulfur dioxide is obtained by injecting sulfur dioxide microbubbles into an acid electrolyte.

8 . The method according to claim 1 , wherein a pH of the aqueous solution absorbed with the sulfur dioxide is adjusted to be less than 5 during the electrochemical reduction.

9 . The method according to claim 6 , wherein a potential of the working electrode is controlled to −0.1 V to −2.0 V versus a reference electrode during the electrochemical reduction.

10 . The method according to claim 2 , wherein the electrochemical reduction of the sulfur dioxide absorbed in the aqueous solution is carried out by using a three-electrode system with the aqueous solution absorbed with the sulfur dioxide as a cathode compartment electrolyte and the membrane electrode as a working electrode.

11 . The method according to claim 3 , wherein the electrochemical reduction of the sulfur dioxide absorbed in the aqueous solution is carried out by using a three-electrode system with the aqueous solution absorbed with the sulfur dioxide as a cathode compartment electrolyte and the membrane electrode as a working electrode.

12 . The method according to claim 4 , wherein the electrochemical reduction of the sulfur dioxide absorbed in the aqueous solution is carried out by using a three-electrode system with the aqueous solution absorbed with the sulfur dioxide as a cathode compartment electrolyte and the membrane electrode as a working electrode.

13 . The method according to claim 5 , wherein the electrochemical reduction of the sulfur dioxide absorbed in the aqueous solution is carried out by using a three-electrode system with the aqueous solution absorbed with the sulfur dioxide as a cathode compartment electrolyte and the membrane electrode as a working electrode.

14 . The method according to claim 6 , wherein the aqueous solution absorbed with the sulfur dioxide is obtained by absorbing the sulfur dioxide into lye or water, or the aqueous solution absorbed with the sulfur dioxide is obtained by injecting sulfur dioxide microbubbles into an acid electrolyte.

15 . The method according to claim 6 , wherein a pH of the aqueous solution absorbed with the sulfur dioxide is adjusted to be less than 5 during the electrochemical reduction.

Assignees

• Univ Central South

Inventors

• Liu Hui
• Xiang Kaisong
• Chai Liyuan
• Shen Fenghua
• Liu Xudong
• Zhu Fangfang
• Wu Lin
• Yi Huimin
• Min Xiaobo
• Lin Zhang
• Li Qingzhu
• Wang Qingwei
• Wang Haiying
• Yang Weichun

Classifications

• C25B11/057

  consisting of a single element or compound · CPC title

• C25B9/23 Primary

  comprising ion-exchange membranes in or on which electrode material is embedded · CPC title

• C25B15/08

  Supplying or removing reactants or electrolytes; Regeneration of electrolytes · CPC title

• B01D53/78

  with gas-liquid contact · CPC title

• B01D53/502

  characterised by a specific solution or suspension · CPC title