Use of an oxidising alkaline gel to remove a biofilm on a surface of a solid substrate

Patent metadata

Field	Value
Publication number	US-9834744-B2
Application number	US-201415101840-A
Country	US
Kind code	B2
Filing date	Dec 3, 2014
Priority date	Dec 5, 2013
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

The use of a gel consisting of a colloidal solution comprising, preferably consisting of: 5% to 30% by weight, preferably 5% to 25% by weight, more preferably 8% to 20% by weight relative to the weight of the gel, of at least one inorganic viscosifying agent; a mineral base selected from among hydroxides of alkaline metals, hydroxides of alkaline-earth metals and the mixtures thereof, said mineral base being present in a proportion of 0.05 to 10 mol/L of gel, preferably in a proportion of 0.1 to 5 mol/L of gel; an oxidizing agent stable in a basic medium selected from among permanganates, persulfates, ozone, hypochlorites and the mixtures thereof, said oxidizing agent stable in a basic medium being present in a proportion of 0.05 to 5 mol/L of gel, preferably 0.1 to 2 mol/L of gel; 0.1% to 2% by weight relative to the weight of the gel, of at least one surfactant; and a solvent; the gel not containing any super-absorbent polymer, to remove a biofilm present on a surface of a solid substrate.

First claim

The invention claimed is:

1. A method, comprising removing a biofilm present on a surface of a solid substrate with a gel, wherein the gel is a colloidal solution comprising:
5% to 30% by weight, relative to the weight of the gel, of at least one inorganic viscosifying agent;
a mineral base selected from the group consisting of hydroxides of alkaline metals, hydroxides of alkaline-earth metals and mixtures thereof, said mineral base being present in a proportion of 0.05 to 10 mol/L of gel;
an oxidising agent stable in a basic medium selected from the group consisting of permanganates, persulfates, ozone, hypochlorites and the mixtures thereof, said oxidising agent stable in a basic medium being present in a proportion of 0.05 to 5 mol/L of gel;
0.1% to 2% by weight relative to the weight of the gel, of at least one surfactant;
and a solvent;
the gel not containing any super-absorbent polymer.

2. The method according to claim 1 , wherein the mineral base is selected from among sodium hydroxide, potassium hydroxide and mixtures thereof, and the oxidising agent stable in the basic medium is selected from hypochlorites and mixtures thereof.

3. The method according to claim 2 , wherein the gel comprises a combination of sodium hydroxide and sodium hypochlorite.

4. The method according to claim 1 , wherein the inorganic viscosifying agent is selected from the group consisting of metal oxides, metalloid oxides with the exception of silica, metal hydroxides, metalloid hydroxides, metal oxyhydroxides, metalloid oxyhydroxides, aluminosilicates, clays, and the mixtures thereof.

5. The method according to claim 4 , wherein the inorganic viscosifying agent consists of one or more aluminas.

6. The method according to claim 5 , wherein the aluminas represent 5% to 30% by weight, relative to the total weight of the gel.

7. The method according to claim 1 , wherein the surfactant is selected from among non-ionic surfactants; and the mixtures thereof.

8. The method according to claim 1 , wherein the solvent is selected from the group consisting of water, organic solvents and the mixtures thereof.

9. The method according to claim 1 , wherein the gel further comprises one or more mineral pigments.

10. The method according to claim 1 , wherein the substrate comprises at least one material selected from the group consisting of metals and alloys; painted steels; organic polymers; glasses; cement materials; plasters; bricks; roof tiles; baked or unbaked earth; natural or artificial stones; coats; glass fibre; fibro-cements; asphalt; tar; slate; cellulose-based materials; and ceramics.

11. The method according to claim 1 , wherein at least one cycle is performed comprising the following:
a) applying the gel on said surface;
b) maintaining the gel on the surface at least for a sufficient time so that the gel destroys the biofilm, and so that the gel dries and forms a dry, solid, non-powdery residue comprising compounds resulting from destruction of the biofilm; and
c) removing the dry, solid, non-powdery residue comprising the compounds resulting from destruction of the biofilm.

12. The method according to claim 11 , wherein the gel is applied to the surface of the solid substrate in the proportion of 100 g to 2000 g of gel per m 2 of surface area.

13. The method according to claim 11 , wherein the gel is applied on the surface of the solid substrate by spraying, or using a brush or float.

14. The method according to claim 1 , wherein the b) drying is conducted at a temperature of 1° C. to 50° C., under a relative humidity of 20% to 80%.

15. The method according to claim 11 , wherein the gel is maintained on the surface for a time of 2 to 72 hours.

16. The method according to claim 11 , wherein the dry, solid residue is in the form of particles having a size from 1 to 10 mm.

17. The method according to claim 11 , wherein the dry, solid, non-powdery residue is removed from the surface of the solid substrate by brushing and/or suction.

18. The method according to claim 11 , wherein the described cycle is repeated 1 to 10 times using the same gel for all cycles or using different gels for one or more cycles.

19. The method according to claim 11 , wherein during the maintaining b), the gel, before complete drying, is re-wetted with a solution of mineral base and oxidising agent.

20. The method according to claim 7 , wherein the non-ionic surfactants are selected from block copolymers, ethoxylated fatty acids; and the mixtures thereof.

21. The method according to claim 20 , wherein said block copolymers are block copolymers of ethylene oxide and propylene oxide.

Assignees

• Commissariat Energie Atomique
• Commissariat L Energie Atomique Et Aux Energies Alternatives

Inventors

• Ludwig Amelie
• Goettmann Frederic
• Frances Fabien
• Castellani Romain

Classifications

• C11D3/3956

  Liquid compositions · CPC title

• C11D3/3947

  Liquid compositions · CPC title

• C11D3/3707

  Polyethers, e.g. polyalkyleneoxides · CPC title

• C11D3/1213

  Oxides or hydroxides, e.g. Al2O3, TiO2, CaO or Ca(OH)2 · CPC title

• C11D11/0041

  Chemistry & Metallurgy · mapped topic