Method for removal of contaminants from surfaces
AssigneeActive Environmental Technologies, Inc.
InventorsRonald E. Borah, Michael W. Bonem
Life of this patent
Estimating the term…
Abstract
Cleaning processes and water-based cleaning compositions effective for the removal of radionuclides, polychlorinated biphenyls, pesticides, herbicides, and heavy metals from surfaces of all types, more especially porous surfaces, surfaces that contain irregularities and microscopic voids into which contaminants may migrate and lodge thereby creating a substrate below the surface that must also be cleaned, and particulate surfaces. The cleaning blends and processes remove contaminants from porous and irregular surfaces to such a depth below the surface and into the substrate, and to such an extent, that the cleaned surface satisfies current regulations promulgated by the EPA and NRC relating to standards for decontamination.
Claims27
A method for removing contaminants from surfaces and the substrates of such surfaces, including porous surfaces, particulate surfaces, and surfaces with irregularities into which the contaminants may migrate or lodge, the method comprising:
- immersing the surface in a low pH oxidation bath having a predetermined temperature and for a predetermined time, said low pH oxidation bath comprising about 2 weight percent to about 20 weight percent nitric acid;
- and
- immersing the surface in a low pH reduction bath having a predetermined temperature and for a predetermined time, said low pH reduction bath comprising about 0.4 weight percent to about 10 weight percent of an acid able to extract cations from the contaminated surface, about 0.5 weight percent to about 10 weight percent of a composition that produces hydrofluoric acid in aqueous solution, about 0.1 weight percent to about 4 weight percent of a surfactant and about 0.8 weight percent to about 14 weight percent of a chelating agent able to fix soluble metals in the contaminants.
A method for removing contaminants from surfaces and the substrates of such surfaces, including porous surfaces, particulate surfaces, and surfaces with irregularities into which the contaminants may migrate or lodge, the method comprising:
- immersing the surface in a low pH oxidation bath having a predetermined temperature and for a predetermined time, said low pH oxidation bath comprising about 2 weight percent to about 20 weight percent nitric acid, about 1 weight percent to about 10 weight percent phosphate acid ester;
- and
- immersing the surface in a low pH reduction bath having a predetermined temperature and for a predetermined time, said low pH reduction bath comprising about 0.4 weight percent to about 10 weight percent sulfamic acid, about 0.5 weight percent to about 10 weight percent ammonium biflouride, about 0.2 weight percent to about 6 weight percent hydrochloric acid, about 0.1 weight percent to about 4 weight percent surfactant, about 0.8 weight percent to about 14 weight percent sodium citrate, about 0.1 weight percent to about 6 weight percent phosphate acid ester, and optionally, about 0.1 to about 2 weight percent d-limonine.
A method for removing contaminants from surfaces and the substrates of such surfaces, including porous surfaces, particulate surfaces, and surfaces with irregularities into which the contaminants may migrate or lodge, the method comprising:
- immersing the surface in a low pH oxidation bath having a predetermined temperature and for a predetermined time, said low pH oxidation bath comprising about 2 weight percent to about 20 weight percent nitric acid;
- immersing the surface in a low pH reduction bath having a predetermined temperature and for a predetermined time, said low pH reduction bath comprising about 0.4 weight percent to about 10 weight percent of an acid able to extract cations from the contaminated surface, about 0.5 weight percent to about 10 weight percent of a composition that produces hydrofluoric acid in aqueous solution, about 0.1 weight percent to about 4 weight percent of a surfactant and about 0.8 weight percent to about 14 weight percent of a chelating agent able to fix soluble metals in the contaminants;
- and
- immersing the surface in a high pH extraction bath having a predetermined temperature and for a predetermined time, said high pH extraction bath comprising:
- about 0.5 weight percent to about 8 weight percent of a surfactant;
- about 0.4 weight percent to about 9 weight percent of a hydrocarbon emulsifier;
- about 0.1 weight percent to about 20 weight percent of a chelating agent for holding solubilized metal ions and particulates in suspension;
- about 0.5 weight percent to about 12 weight percent of a degreasing agent for removing hydrocarbons from the contaminated surface;
- about 0.3 weight percent to about 8 weight percent of a wetting agent;
- and about 0.3 weight percent to about 8 weight percent of a hydrotropic agent.
Dependencies are inferred from the claim text.