Process and installation for the destruction of organic solutes, particularly complexing agents, present in an aqueous solution such as a radioactive effluent

• US 5,536,389 A
• Filed: 03/08/1995
• Issued: 07/16/1996
• Est. Priority Date: 03/16/1994
• Status: Expired due to Term

• Current Assignee: Compagnie Generale DES Etablissements Michelin SCA
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation), Compagnie Generale DES Etablissements Michelin SCA
• Inventors: Moisy, Philippe, La Naour, Claire, Madic, Charles
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): PHASGE, ARUN S
• Application Number:
  US08/400,659
• Time in Patent Office: 496 Days
• Field of Search: 204/131, 204/78, 204/149, 588/204, 205/688, 205/742, 205/744
• US Class Current: 205/688
• CPC Class Codes: C02F 1/46104 Devices therefor; Their operating or servicing
• CPC Class Codes: C02F 1/4672 by electrooxydation
• CPC Class Codes: C02F 2001/46133 characterised by the material
• CPC Class Codes: C02F 2001/46152 characterised by the shape or form electrodes in particulate form or with conductive or non-conductive particles between them C02F1/46114
• CPC Class Codes: C02F 2101/006 Radioactive compounds
• CPC Class Codes: C02F 2101/303 Complexing agents
• CPC Class Codes: C02F 2201/4611 Fluid flow
• CPC Class Codes: C02F 2201/46125 Electrical variables
• CPC Class Codes: C02F 2201/4615 Time
• CPC Class Codes: C02F 2201/4619 Supplying gas to the electrolyte gas diffusion electrodes C02F2001/46166
• CPC Class Codes: G21F 9/06 Processing separating different isotopes of the same chemical element B01D59/00

Abstract

The invention relates to a process and an installation for the destruction of organic solutes, particularly complexing agents, present in an aqueous solution such as a radioactive effluent.

According to this process, the aqueous solution undergoes electrolysis in a cell (1) comprising a working electrode (5₁, 5₂, etc.) by applying to said electrode an adequate potential for destroying the solutes by electrolytic oxidation and periodic modification takes place to the potential applied or to the passage direction of the current passing through the cell so as to periodically carry out a regeneration of the working electrode.

The solutes can be organic acids such as formic acid, dihydroxymalonic acid or oxalic acid.

Claims

1. Process for the destruction of at least one organic solute present in an aqueous solution, comprising the steps of electrolyzing the aqueous solution in an electrolytic cell without a diaphragm using three electrodes including a working electrode by applying to the working electrode an adequate potential for destroying the solute or solutes by electrolytic oxidation, and periodically modifying the potential applied to the working electrode to regenerate the working electrode.

2. Process according to claim 1, characterized in that electrolysis takes place according to the potentiostatic mode and in that periodic modification takes place of the potential of the working electrode so as to perform successive cycles, each comprising a first electrolysis stage at a potential E₁ for a time t₁ and a second electrolysis stage at a potential E₂ for a time t₂.

3. Process according to claim 2, characterized in that t₁ is 20 to 1200 seconds.

4. Process according to claim 2, characterized in that t₂ is 5 to 60 seconds.

5. Process according to claim 2, characterized in that the difference between E₁ and E₂ is 0.5 to 2 V.

6. Process according to claim 1, characterized in that the organic solute is a complexing organic solute chosen from among carboxylic, hydroxycarboxylic, polycarboxylic, polyhydroxypolycarboxylic, aminocarboxylic and polyaminopolycarboxylic acids.

7. Process according to claim 6, characterized in that the complexing organic solute is formic, dihydroxymalonic or oxalic acid.

8. Process according to claim 1, characterized in that the aqueous solution is a radioactive effluent.

9. Process for the destruction of at least one organic solute present in an aqueous solution comprising the steps of electrolyzing the solution according to the intensiostatic mode in an electrolytic cell without a diaphragm and including two electrodes by applying to one of the electrodes an adequate potential for destroying the solute or solutes by electrolytic oxidation, and periodically reversing the direction of the current in the cell so as to perform successive cycles, each comprising a first stage at a current intensity I for a time t₁ and a second stage at the same intensity, but with a reversed current for a time t₂.

10. Process according to claim 9, characterized in that t₁ is equal to t₂.

11. Process according to claim 9, characterized in that t₁ and t₂ are 10 to 100 s.

12. Process according to claim 9, characterized in that the intensity of the current is 4 to 20 mA/cm².