Adsorbent and photocatalytic decontamination gel, and method for decontaminating surfaces using said gel

Patent metadata

Field	Value
Publication number	US-11517640-B2
Application number	US-201716316686-A
Country	US
Kind code	B2
Filing date	Jul 12, 2017
Priority date	Jul 13, 2016
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

An adsorbent and photocatalytic decontamination gel consisting of a colloidal solution comprising, preferably consisting of: 8% to 30% by weight, preferably 10% to 30% by weight, more preferably 15% to 20% by weight, better still 15% to 20% by weight, the value 15% being excluded, even better still 16% to 20% by weight, for example 20% by weight of TiO2, optionally doped, relative to the weight of the gel; optionally 0.01% to 10% by weight, preferably 0.1% to 5% by weight, relative to the weight of the gel, of at least one dye and/or of at least one pigment; optionally 0.1% to 2% by weight, relative to the weight of the gel, of at least one surfactant; optionally 0.05% to 5% by weight, preferably 0.05% to 2% by weight, relative to the weight of the gel, of at least one superabsorbent polymer; and the balance of solvent.

First claim

What is claimed is:

1. Adsorbent and photocatalytic decontamination gel consisting of a colloidal solution comprising:
15% to 20% by weight of TiO2, optionally doped, relative to the weight of the gel;
optionally, 0.01% to 10% by weight relative to the weight of the gel of at least one dye and/or at least one pigment;
optionally, 0.1% to 2% by weight relative to the weight of the gel, of at least one surfactant;
optionally, 0.05% to 5% by weight relative to the weight of the gel, of at least one super-absorbent polymer;
and the balance solvent, said solvent being selected from among mixtures of water in a proportion of 40% to 56% by weight, and of ethanol, in a proportion of 24% to 42.5% by weight relative to the weight of gel;
and said gel having a pH of 4 or higher.

2. The gel according to claim 1 having a weak acidic pH of 4 to less than 7; or a neutral pH of 7; or a weak basic pH of more than 7 to less than 9; or a very basic pH of 9 or higher.

3. The gel according to claim 1 , wherein the pH of the gel is adjusted by the addition of a mineral base.

4. The gel according to claim 1 , wherein the TiO2 is in the form of particles of a mean size of 2 to 200 nm.

5. The gel according to claim 1 having a storage time of at least one year.

6. The method for decontaminating at least one surface of a substrate made of a solid material, said surface being contaminated by at least one contaminating species on said surface, wherein at least one cycle is performed comprising the following successive steps:
a) applying the gel according to claim 1 on said surface;
b) maintaining the gel on the surface at least for a sufficient time for the gel to absorb the contaminating species, for the contaminating species then to be adsorbed on the surface of the TiO2 particles, and for the gel to dry and form a dry and solid residue containing said contaminating species adsorbed on the surface of the TiO2 particles;
c) removing the dry and solid residue containing said contaminating species adsorbed in the gel on the surface of the TiO2 particles.

7. The method according to claim 6 , wherein the substrate is made of at least one solid material selected from among metals and metal alloys; polymers; glasses; cements and cement materials; mortars and concretes; plasters; bricks; natural or artificial stone; and ceramics.

8. The method according to claim 6 , wherein the contaminating species is selected from among ionic, chemical, biological, nuclear or radioactive contaminating species.

9. The method according to claim 8 , wherein the contaminating species is an ionic contaminating species selected from among monovalent and multivalent metal ions.

10. The method according to claim 8 , wherein the contaminating species is a biological contaminating species selected from among biotoxic species, bacteria, fungi, yeasts, viruses, toxins, pathogenic spores, prions, and protozoa.

11. The method according to claim 8 , wherein the contaminating species is selected from among toxic gaseous chemical species.

12. The method according to claim 6 , wherein the gel is applied to the surface to be decontaminated in a proportion of 100 g to 2000 g of gel per m2 of surface area, which generally corresponds to a gel thickness deposited on the surface of 0.1 mm to 2 mm.

13. The method according to claim 6 , wherein the gel is applied to the solid surface by spraying, with a brush or with a float.

14. The method according to claim 6 , wherein during all or part of step a), and/or during all or part of step b), the gel maintained on the surface is exposed to a visible radiation or to a A, B or C Ultraviolet radiation (UVA, UVB or UVC), or to another radiation, to inactivate, and/or degrade, and/or reduce, and/or destroy the contaminating species by photocatalysis.

15. The method according to claim 6 , wherein (during step b), drying is carried out at a temperature of 1° C. to 50° C., and under a relative humidity of 20% to 80%.

16. The method according to claim 6 , wherein the gel is maintained on the surface for a time of 2 to 72 hours.

17. The method according to claim 6 , wherein the dry, and solid residue is in the form of particles of a size of 1 to 10 mm.

18. The method according to claim 6 , wherein the dry solid residue is removed from the solid surface by brushing and/or vacuuming, suction.

19. The method according to claim 6 , wherein the cycle is repeated 1 to 10 times using the same gel for each cycle, or using different gels for one or more cycle(s).

20. The method according to claim 6 wherein during step b) the gel, before complete drying, is rewetted with a solvent, preferably with the solvent of the gel applied during step a).

21. Adsorbent and photocatalytic decontamination gel consisting of a colloidal solution consisting of:
15% to 20% by weight of TiO2, optionally doped, relative to the weight of the gel;
optionally, 0.01% to 10% by weight relative to the weight of the gel of at least one dye and/or at least one pigment;
optionally, 0.1% to 2% by weight relative to the weight of the gel, of at least one surfactant;
optionally, 0.05% to 5% by weight relative to the weight of the gel, of at least one super-absorbent polymer;
and the balance solvent, said solvent being selected from among mixtures of water in a proportion of 40% to 56% by weight, and of ethanol, in a proportion of 24% to 42.5% by weight relative to the weight of gel;
and said gel having a pH of 4 or higher.

22. The gel according to claim 3 , wherein the mineral base is selected from among sodium hydroxide, potassium hydroxide, and mixtures thereof.

23. The method according to claim 6 , wherein said surface is further contaminated by at least one contaminating species below said surface, in the depth of the substrate.

24. The method according to claim 7 , wherein the substrate is made of at least one metals or metal alloy selected from the group consisting of stainless steel, painted steels, aluminium and lead.

25. The method according to claim 7 , wherein the substrate is made of at least one polymer wherein the polymer is a plastic material or a rubber.

26. The method according to claim 25 , wherein the plastic material or rubber is selected from the group consisting of poly(vinyl chloride)s, polypropylenes, polyethylenes, high density polyethylenes, poly(methyl methacrylate)s, poly(vinylidene fluoride)s, and polycarbonates.

27. The method according to claim 9 , wherein the monovalent and multivalent metal ions are selected from the group consisting of chromium (VI), nickel (II), silver (I), cadmium (II), mercury (II), arsenic (III) and lead (II) ions.

28. The method according to claim 10 , wherein the contaminating species is pathogenic spores.

29. The method according to claim 28 , wherein the pathogenic spores is spores of Bacillus anthracis.

30. The method according to claim 10 , wherein the biological contaminating species is a toxin selected from the group consisting of botulinum toxin or ricin.

31. The method according to claim 10 , wherein the biological contaminating species is a Yersinia pestis bacteria.

32. The method according to claim 10 , wherein the biological contaminating species is a vaccine virus.

33. The method according to claim 10 , wherein the biological contaminating species is

Assignees

• Commissariat Energie Atomique

Inventors

• Gossard Alban
• Frances Fabien
• Lepeytre Célia

Classifications

• A61L2103/00

  Materials or objects being the target of disinfection or sterilisation · CPC title

• A62D2101/02

  Chemical warfare substances, e.g. cholinesterase inhibitors · CPC title

• A61L2/26

  Accessories · CPC title

• B01J20/06

  comprising oxides or hydroxides of metals not provided for in group B01J20/04 · CPC title

• A62D3/33

  by chemical fixing the harmful substance, e.g. by chelation or complexation · CPC title