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CN-121983607-A - Eluent for membrane electrode in waste fuel cell, preparation method and application method

CN121983607ACN 121983607 ACN121983607 ACN 121983607ACN-121983607-A

Abstract

The invention discloses an eluent for a membrane electrode in a waste fuel cell, a preparation method and an application method thereof, wherein the eluent comprises a reducing agent, a decomposing agent and a dissolving agent, the dissolving agent comprises a dissolving agent A and a dissolving agent B, the dissolving agent A comprises mixed alcohol and water, the dissolving agent B is one or more selected from dichloromethane, chloroform and hexane, and during the preparation, the dissolving agent B is firstly added into the dissolving agent A, stirred and mixed uniformly to prepare the dissolving agent, and then the reducing agent and the decomposing agent are added into the dissolving agent, stirred and mixed uniformly. When the eluent is applied, the catalyst layer and the proton exchange membrane can be completely separated from each other, the elution rate is more than 99.5%, the damage of the eluent to the proton exchange membrane is avoided, and the synchronous protection of the proton exchange membrane is realized while the effective elution is realized.

Inventors

  • LIAO TIANYU
  • SHI YINGFEI
  • WANG CHENYANG
  • WANG TIANYI
  • SHI JUNFENG

Assignees

  • 江苏铂源催化科技有限公司
  • 江苏龙蟠科技集团股份有限公司

Dates

Publication Date
20260505
Application Date
20260128

Claims (7)

  1. 1. The eluent for the membrane electrode of the waste fuel cell is characterized by comprising a reducing agent, a decomposing agent and a dissolving agent in a volume ratio of (1-4) 2 (6-70); the dissolving agent comprises a dissolving agent A and a dissolving agent B in a volume ratio of (5-9) (1-4), wherein the dissolving agent A comprises mixed alcohol and water in a volume ratio of (1-5), and the dissolving agent B is one or more of dichloromethane, chloroform and hexane; The reducing agent is one or more of potassium bromide, potassium iodide, sodium bromide or sodium borohydride; The decomposer is one or more of acetone, ethyl acetate, toluene and N-N dimethylformamide.
  2. 2. The eluent as claimed in claim 1, wherein said mixed alcohol is a mixed solution of two or more of ethanol, methanol, isopropanol, glycerol or ethylene glycol.
  3. 3. The eluent as claimed in claim 2, wherein said mixed alcohol is ethanol and glycol in a volume ratio of (2-6): 1.
  4. 4. The eluent as claimed in claim 3, wherein the mixed alcohol is ethanol and glycol in a volume ratio of (2.5-3): 1.
  5. 5. The eluent as claimed in claim 1, wherein said dissolving agent B is methylene chloride and hexane in a volume ratio of (2-3): (1-6).
  6. 6. A method of preparing the eluent of any one of claims 1 to 5, comprising the steps of: (1) Adding the dissolving agent B into the dissolving agent A according to the volume ratio, and stirring and uniformly mixing to prepare the dissolving agent; (2) Adding a reducing agent and a decomposing agent into the dissolving agent in the step (1) according to the volume ratio, and stirring and mixing uniformly to obtain the eluent.
  7. 7. A method for applying the eluent in any one of claims 1-5, which is characterized by comprising the following steps of adding a membrane electrode of a waste fuel cell into the eluent according to a mass ratio of 1 (5-15), eluting for 4-6 hours at a temperature of 30-60 ℃, and filtering and separating to obtain catalyst slurry and a proton exchange membrane respectively.

Description

Eluent for membrane electrode in waste fuel cell, preparation method and application method Technical Field The invention belongs to the field of catalyst separation and recovery in a cell MEA, and particularly relates to an eluent for a membrane electrode in a waste fuel cell, a preparation method and an application method. Background Membrane Electrodes (MEA) in Proton Exchange Membrane Fuel Cells (PEMFC) are typically constructed of seven layers of anode diffusion layer, anode porous carbon layer, anode catalytic layer, electrolyte membrane, cathode catalytic layer, cathode porous carbon layer and cathode diffusion layer hot pressed together. Wherein the catalytic layer is composed of a catalyst composed of platinum carbon or a part of iridium oxide and a solid polymer electrolyte. After the membrane electrode works in the fuel cell for a certain time, the fuel cell cannot be used due to external pollution or aggregation of the catalyst, but the physicochemical properties of noble metals such as platinum and iridium in the catalytic layer of the waste fuel cell are not changed, and the catalytic activity is reduced. Therefore, the catalyst and the proton membrane can be separated, and the noble metals in the proton membrane and the catalyst can be recovered. In order to better separate the membrane from the catalyst layer, the applicant has previously studied an eluent for separating the PTFE layer from the catalyst of the waste fuel cell, wherein the eluent is a mixed system composed of a dissolving agent, a reducing agent and a decomposing agent, and the dissolving agent is a mixed solution of absolute ethanol and ethylene glycol. The preparation method comprises mixing absolute ethanol with ethylene glycol to obtain a dissolving agent, adding a reducing agent (such as potassium bromide) and a decomposing agent (such as toluene) into the above dissolving agent, and mixing to obtain an eluent. In the eluting process, the PTFE layer (with the platinum content of 0.6%) of the waste fuel cell needs to be crushed in advance and then added into an eluent, the mixture is stirred for eluting, and the mixture is filtered by a screen after the end of the eluting process to obtain slurry containing the platinum carbon catalyst and the eluted PTFE layer of the waste fuel cell, wherein the eluted PTFE layer is white and basically has no platinum carbon residue, the eluted PTFE layer also has no damage and corrosion, the eluting effect is better, and the measured eluting rate is 99.7%. However, in the above-mentioned scheme, the eluting target for the eluent is a single layer of PTFE, and the catalyst is directly coated on the PTFE, which is a semi-finished membrane electrode known in the art. In addition, PTFE itself is strong in acid, alkali and corrosion resistance, and the eluent itself has little effect. The membrane electrode is a proton exchange membrane, the main material of which is a perfluorosulfonic acid membrane, acid resistance, alkali resistance and corrosion resistance are weaker, and the risk of damage easily occurs in the eluting process, so that the membrane is damaged, and the protection of the membrane itself is required to be paid attention to in the eluting process. Based on the above, a novel eluent is designed on the basis of the eluent developed in the prior art, so that the separation elution of the catalyst layer, the carbon paper and the proton exchange membrane on the finished membrane electrode with more complex components is realized, and meanwhile, the proton exchange membrane is protected, and unnecessary damage caused in the elution process is prevented. Disclosure of Invention The invention aims to provide the eluent, the preparation method and the application method, which not only can effectively elute and separate the catalyst layer in the membrane electrode from the proton exchange membrane, but also can avoid damaging the proton exchange membrane. The invention adopts the technical proposal that the eluent for the membrane electrode in the waste fuel cell comprises a reducing agent, a decomposing agent and a dissolving agent with the volume ratio of (1-4) being 2 (6-70); the dissolving agent comprises a dissolving agent A and a dissolving agent B in a volume ratio of (5-9) (1-4), wherein the dissolving agent A comprises mixed alcohol and water in a volume ratio of (1-5), and the dissolving agent B is one or more of dichloromethane, chloroform and hexane; The reducing agent is one or more of potassium bromide, potassium iodide, sodium bromide or sodium borohydride; The decomposer is one or more of acetone, ethyl acetate, toluene and N-N dimethylformamide. Further, the mixed alcohol used in the eluent can be a mixed solution of two or more of ethanol, methanol, isopropanol, glycerol or glycol. Preferably, the mixed alcohol can be ethanol and glycol in a volume ratio of (2-6): 1. Further preferably, the mixed alcohol may be ethanol and ethylene glycol in a volume ratio of (2.5-3