METHODS FOR DECOMPOSING PARTIALLY FLUORINATED AND PERFLUORINATED SURFACTANTS

• US 20120055807A1
• Filed: 03/09/2010
• Published: 03/08/2012
• Est. Priority Date: 03/09/2009
• Status: Active Grant

• Current Assignee: Hansgrohe AG
• Original Assignee: Hansgrohe AG
• Inventors: Fath, Andreas
• Granted Patent: US 9,221,695 B2
• Time in Patent Office: Days
• US Class Current: 205/756
• CPC Class Codes: C02F 1/4672 by electrooxydation
• CPC Class Codes: C02F 2001/46138 Electrodes comprising a substrate and a coating
• CPC Class Codes: C02F 2001/46157 Perforated or foraminous electrodes
• CPC Class Codes: C02F 2101/301 Detergents, surfactants
• CPC Class Codes: C02F 2101/36 containing halogen
• CPC Class Codes: C02F 2103/16 from metallurgical processes, i.e. from the production, refining or treatment of metals, e.g. galvanic wastes
• CPC Class Codes: C02F 2103/30 from the textile industry
• CPC Class Codes: C02F 2103/40 from the manufacture or use of photosensitive materials

Abstract

In a method of decomposing partially fluorinated and perfluorinated surfactants which are, in particular, present in wastewater, sewage sludges and the like, the surfactant is present in solution or suspension and is electrolytically decomposed. An anodic oxidation of the surfactants preferably takes place here. The method is particularly suitable for decomposing perfluorinated alkylsulfonates, in particular PFOS.

The invention also describes an apparatus for electrolytically decomposing partially fluorinated and perfluorinated surfactants.

Claims

1. A method comprising decomposing partially fluorinated and perfluorinated surfactants (PFSs) which are, in particular, present in wastewater, sewage sludges and the like, wherein the surfactant is present in at least one of solution and suspension and is electrolytically decomposed.

2. The method as claimed in claim 1, wherein the decomposition is effected by anodic oxidation.

3. The method as claimed in claim 2, wherein the anodic oxidation takes place at an anode comprising at least one of titanium, platinum-plated titanium, lead and lead alloy.

4. The method as claimed in claim 1, wherein the method is carried out at a current density in a range of 1 A/dm² to 6 A/dm².

5. The method as claimed in claim 1, wherein the method is carried out at a voltage in a range of 3 V to about 15 V.

6. The method as claimed in claim 1, wherein the method is carried out over a period of at least 0.5 hour to at least 10 hours.

7. The method as claimed in claim 1, wherein the perfluorinated surfactant comprises a perfluorinated alkylsulfonate (PFAS).

8. The method as claimed in claim 7, wherein the perfluorinated alkylsulfonate comprises perfluorooctanesulfonate (PFOS).

9. The method as claimed in claim 7, wherein the perfluorinated alkylsulfonate comprises perfluorobutanesulfonate (PFBS).

10. The method as claimed in claim 1, wherein the partially fluorinated surfactant comprises H4-perfluorooctyl-sulfonate (H4 PFOS).

11. The method as claimed in claim 1, wherein the method is carried out continuously.

12. The method as claimed in claim 1, wherein the method is carried out as a flow process.

13. The method as claimed in claim 1, comprising electrolytically decomposing the surfactants using at least one electrode configured in such a way that the at least one of the solution and suspension is passed through this electrode.

14. The method as claimed in claim 1, wherein the surfactants that are decomposed originate from electroplating wastewater.

15. The method as claimed in claim 14, wherein the surfactants that are decomposed originate from wastewater obtained in chromium plating of parts comprising one of metal and plastic parts.

16. The method as claimed in claim 14, wherein the surfactants that are decomposed originate from wastewater obtained in electroplating of sanitary articles.

17. A method for decomposing partially fluorinated and perfluorinated surfactants (PFSs) present in a liquid comprising wastewater, sewage sludges and the like, comprising applying electrolysis to the liquid.

18. An apparatus (1) for electrolytically decomposing partially fluorinated and perfluorinated surfactants which are, in particular, present in a liquid of wastewater, sewage sludges and the like, comprising:

a vessel configured to hold the liquid, at least one electrode which can be connected to a source of electric power via a cathode (4) and at least one electrode which can be connected as an anode (3), with at least two electrode pairs consisting of anode (3) and cathode (4) being applied to the liquid.

19. The apparatus as claimed in claim 18, wherein at least one said electrode is configured and arranged in such a way that a solution or suspension containing the surfactants is at least partly passed through this electrode.

20. The apparatus as claimed in claim 18, wherein at least two electrode pairs, each comprising an anode (3) and cathode (4) are arranged one after another.

21. The apparatus as claimed in claim 20, wherein at least four electrode pairs, each comprising an anode (3) and cathode (4) are arranged one after the other.

22. The apparatus as claimed in claim 18, wherein the electrode pairs are arranged in an array.

23. The apparatus as claimed in claim 18, wherein at least some of the anodes (3) are anodes (3) comprising one of titanium and platinum-plated titanium.

24. The apparatus as claimed in claim 23, wherein the anodes comprise titanium wire compacts.

25. The apparatus as claimed in claim 18, wherein at least some of the anodes (3) comprise one of lead and lead alloy.

26. The apparatus as claimed in claim 18, wherein at least some of the cathodes (4) comprise one of lead and lead alloy.