Patent Application
20070185002
Field of the Invention: Compositions and methods for decontaminating surfaces. More specifically, compositions and methods for decontamination using a composition capable of generating a long lasting foam
State of the Art: Several countries and international groups, many of them hostile to the United States and its allies, currently possess or are seeking to develop the capability to produce nuclear, biological and/or chemical weapons of mass destruction (WMD) and the means to deliver them. Many of these countries and international groups also advocate terrorism as a means to achieve their goals. In order to respond to the threat of terrorism using WMDs, responding agencies at all levels of government (i.e. local, state, and federal) must be adequately prepared to mitigate the hazards to the public and the environment in a timely manner. A particular problem to date has been the manner of cleaning up the potentially toxic residue from terrorist events.
Radiological devices such as nuclear weapons and “dirty bombs” represent an increasingly dangerous threat to society, particularly when they contain radiological materials with long half lives. It is vital that when radiological materials released from such devices that they be quickly and easily cleaned up. Once released, radiological materials present a decontamination problem when deposited on the surfaces of various buildings, equipment, and vehicles, or on the ground.
Biological agents are typically particulate in nature and present a significant hazard long after an attack through formation of secondary aerosols which are inhaled. Further, biological agents may adhere to surfaces or be repositioned in the underlying environment and remain hazardous if disturbed. Thus, biological materials present a continuing decontamination problem when deposited on the surfaces of various buildings, equipment, and vehicles, or on the ground.
Chemical warfare agents may also be long lasting in the environment and many classes of persistent and semi-persistent agents exist. As a consequence, chemical warfare agents may pose a continuing hazard when deposited on the surfaces of various buildings, equipment, and vehicles, or on the ground.
Clearly there is a need for a long lasting formulation that is stable, non-toxic to personnel and the environment, and can support a variety decontamination chemicals selected based on the contamination to be countered. Further, the formulation should be easy to transport to site in a substantially aqueous medium and capable of coating surfaces, including vertical surfaces, for long enough periods of time to begin effective decontamination.
A composition for the decontamination of a contaminated surface is disclosed. The composition comprises a surfactant and gelatin and has a pH of less than about 6. The composition is capable of generating a foam and is compatible with Affinity Shifting Chemical (ASC) materials.
In exemplary embodiment, a surfactant present in the composition for decontamination comprises Silv-ex®, a fire-fighting foam commercially available from Ansul Inc. (Houston, Tex.).
In a further exemplary embodiment, the pH of the composition for decontamination may be less than about 6. Further, the pH may be from about -0.5 to about 6. And yet further, the pH may be 0.3 or 4.5.
In another exemplary embodiment, the composition for decontamination may further comprise Affinity Shifting Chemical (ASC) materials.
A foam for decontamination is also disclosed. The foam comprises a surfactant and gelatin and has a pH of less than about 6
In exemplary embodiment, a surfactant present in the foam for decontamination comprises Silv-ex®, a fire-fighting foam commercially available from Ansul Inc. (Houston, Tex.).
In a further exemplary embodiment, the pH of the foam for decontamination may be less than about 6. Further, the pH may be from about −0.5 to about 6. And yet further, the pH may be 0.3 or 4.5.
In another exemplary embodiment, the composition for decontamination may further comprise Affinity Shifting Chemical (ASC) materials.
A method of decontaminating a surface is also disclosed. The method comprises treating a surface to be decontaminated with a composition according to the present invention. Examples of contamination to be treated include, but are not limited to, biological, chemical, and radiological contamination.
A method of generating a foam is also disclosed. The method comprises providing a composition according to the present invention and injecting a gas into it so as to form a foam.
A method of decontaminating a surface with a foam is also disclosed. The method comprises generating a foam with a composition according to the present invention. The method further comprises treating the surface to be contaminated with the foam generated from the composition according to the present invention.
Before the present compositions and methods of use thereof for decontamination are disclosed and described, it is to be understood that this invention is not limited to the particular configurations, process steps, and materials disclosed herein as such configurations, process steps, and materials may vary somewhat. It is also to be understood that the terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting since the scope of the present invention will be determined by the appended claims and equivalents thereof.
As used herein, “comprising,” “including,” “containing,” “characterized by,” and grammatical equivalents thereof are inclusive or open-ended terms that do not exclude additional, unrecited elements or method acts.
As used herein and in the appended claims, the singular forms, for example, “a”, “an”, and “the,” include the plural, unless the context clearly dictates otherwise. For example, reference to “a surfactant” includes a plurality of such surfactants, and reference to a “chelator” includes a plurality of chelators, and equivalents thereof.
As used herein, “about” means reasonably close to, a little more or less than the stated number or amount, or approximately.
As used herein, “exemplary” means an serving as an example of. The use of the term “exemplary” herein in connection with a particular embodiment is not to be construed as the particular embodiment being preferred over any other embodiment.
Surfactants as used herein include anionic, nonionic, cationic and/or amphoteric or zwitterionic surfactants. Examples of anionic surfactants include, but are not limited to, soaps, alkyl benzenesulfonates, alkanesulfonates, olefin sulfonates, alkylether sulfonates, glycerol ether sulfonates, .alpha.-methyl ester sulfonates, sulfofatty acids, alkyl sulfates, fatty alcohol ether sulfates, glycerol ether sulfates, fatty acid ether sulfates (such as Sodium Lauryl Ether Sulfate (SLS), Ammonium Lauryl Ether Sulfate (ALS), Texapon®, and Silv-ex®), hydroxy mixed ether sulfates, monolyceride (ether) sulfates, fatty acid amide (ether) sulfates, mono- and dialkyl sulfosuccinates, mono- and dialkyl sulfosuccinamates, sulfotriglycerides, amide soaps, ether carboxylic acids and salts thereof, fatty acid isethionates, fatty acid sarcosinates, fatty acid taurides, N-acylamino acids such as, for example, acyl lactylates, acyl tartrates, acyl glutamates and acyl aspartates, alkyl oligoglucoside sulfates, protein fatty acid condensates (particularly wheat-based vegetable products) and alkyl (ether) phosphates. If the anionic surfactants contain polyglycol ether chains, they may have a conventional homolog distribution although they preferably have a narrow-range homolog distribution. Examples of nonionic surfactants include, but are not limited to, fatty alcohol polyglycol ethers, alkylphenol polyglycol ethers, fatty acid polyglycol esters, fatty acid amide polyglycol ethers, fatty amine polyglycol ethers, alkoxylated triglycerides, mixed ethers and mixed formals, optionally partly oxidized alk(en)yl oligoglycosides or glucuronic acid derivatives, fatty acid-N-alkyl glucamides, protein hydrolyzates (particularly wheat-based vegetable products), polyol fatty acid esters, sugar esters, sorbitan esters, polysorbates and amine oxides. If the nonionic surfactants contain polyglycol ether chains, they may have a conventional homolog distribution, although they preferably have a narrow-range homolog distribution. Examples of cationic surfactants include, but are not limited to, quatenary ammonium compounds, for example dimethyl distearyl ammonium chloride, and esterquats, more particularly quaternized fatty acid trialkanolamine ester salts. Examples of amphoteric or zwitterionic surfactants include, but are not limited to, alkylbetaines, alkylamidobetaines, amino-propionates, aminoglycinates, imidazolinium betaines and sulfobetaines.
Gelatin, as used herein refers to a protein product derived through partial hydrolysis of the collagen extracted from skin, bones, cartilage, ligaments, etc. Gelatin is commercially available, for example, from Kraft Foods Inc. (Northfield, IL) under the Knox brand name.
Embodiments of the present invention include compositions for the decontamination of a contaminated surface. One such composition comprises a surfactant and gelatin and has a pH of less than about 6. The composition is capable of generating a foam. Examples of contamination to be treated include, but are not limited to, biological, chemical, and radiological contamination. The stable nature of the composition allows the composition to comprise any number of further chemicals and cleaning agents that would aid in the decontamination of the surface. One advantage of such a compostion is that it is made of non-toxic and environmentally friendly components. In addition, such a composition is compatible with Affinity Shifting Chemical (ASC) materials.
In exemplary embodiment, a surfactant present in the composition for decontamination comprises Silv-ex®, a fire-fighting foam commercially available from Ansul Inc. (Houston, Tex.).
In another exemplary embodiment, the surfactant may be present in the composition for decontamination at 0.1% to 10% by weight. Further the surfactant may be present at 1% by weight.
In an exemplary embodiment, the gelatin may be present in the composition for decontamination at 1% to 10% by weight. Further, the gelatin may be present at 3% by weight.
In a further exemplary embodiment, the pH of the composition for decontamination may be less than about 6. Further, the pH may be from about -0.5 to about 6. And yet further, the pH may be 0.3 or 4.5.
In another exemplary embodiment, the composition for decontamination may further comprise Affinity Shifting Chemical (ASC) materials. Examples of ASCs include, for example, a combination of acetic acid (OHAc) and Sodium acetate (NaOAc) and chelators including, but not limited to, ethylenediaminetetraacetic acid (EDTA), (2-Hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), ethylene glycol-bis-(2-aminoethyl)- tetraacetic acid (EGTA), Ammonium MolyboPhosphate (AMP), triethanolamine (TEA), citrate, and nitrilotriacetic acid (NTA).
Embodiments of the present invention include foam compositions for decontamination. One such foam comprises surfactant and gelatin and has a pH of less than about 6. Examples of contamination that may be treated include, but are not limited to, biological, chemical, and radiological contamination. The stable nature of the foam allows the composition to comprise any number of further chemicals and cleaning agents that would aid in decontamination. One advantage of such a foam is that it is made of non-toxic and environmentally friendly components. A further advantage is that such a foam greatly decreases the volume of solution that must be used to cover the same amount of surface area. In addition, this foam is compatible with Affinity Shifting Chemical (ASC) materials.
In exemplary embodiment, a surfactant present in the foam for decontamination comprises Silv-ex®, a fire-fighting foam commercially available from Ansul Inc. (Houston, Tex.).
In another exemplary embodiment, the surfactant may be present in the foam for decontamination at 0.1% to 10% by weight. Further the surfactant may be present at 1% by weight.
In an exemplary embodiment, the gelatin may be present in the foam for decontamination at 1% to 10% by weight. Further, the gelatin may be present at 3% by weight.
In a further exemplary embodiment, the pH of the foam for decontamination may be less than about 6. Further, the pH may be from about −0.5 to about 6. And yet further, the pH may be 0.3 or 4.5.
In another exemplary embodiment, the foam for decontamination may further comprise Affinity Shifting Chemical (ASC) materials. Examples of ASCs include, for example, a combination of acetic acid (OHAc) and Sodium acetate (NaOAc) and chelators including, but not limited to, ethylenediaminetetraacetic acid (EDTA), (2-Hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), ethylene glycol-bis-(2-aminoethyl)-tetraacetic acid (EGTA), Ammonium MolyboPhosphate (AMP), triethanolamine (TEA), citrate, and nitrilotriacetic acid (NTA).
Embodiments of the present invention include methods of decontaminating a surface. A method comprises treating a surface to be decontaminated with a composition according to the present invention. Examples of contamination to be treated include, but are not limited to, biological, chemical, and radiological contamination.
A method of generating a foam is also disclosed. The method comprises providing a composition according to the present invention and injecting a gas into it so as to form a foam.
A method of decontaminating a surface with a foam is also disclosed. The method comprises generating a foam with a composition according to the present invention. The method further comprises treating the surface to be contaminated with the foam generated from the composition according to the present invention. The long lasting nature of the foam generated by the decontaminating composition allows the application of cleaning agents and chemicals to surfaces, including vertical surfaces, and further allows a long period of contact between the surfaces and the decontamination composition.
Decontamination Compositions
A range of decontamination compositions were created in water. A variety of surfactants and potential foam stabilizers were tested. Reagents used included Triton X-100 (T100), glycerin (GLY), sodium lauryl sulfate (SLS), potassium chloride (KCL), gelatin (gel), ethylene glycol, sodium sterate, potatoe starch, Ansul Silv-Exg (Ansul), n-laurolysoarcosine sodium (sarcosine LS), dioctyl sulfosuccinate sodium (sulfosuccinate DOS), and egg white (Albumin).
Solutions created for testing are provided in Table 1 (all percentages indicate percentage of reagent by weight in the decontamination solution).
Where gelatin was used, it was not added directly to the solution as commercially available. Prior to being added to the decontamination solution, the gelatin was added to cold water and then heated to 200° F.
Foam Production and Decay
Screening of surfactants for foam making purposes was tested using a simple method. The American Society for Testing and Materials (ASTM-3601-88) technique of adding an aqueous solution of the surfactant to a glass bottle was used. The height of the solution in the bottle was measured. The bottle was vigorously shaken and the height of the top of the foam was recorded as a function of time. Aqueous solutions of 0.01 to 1% SLS, 0.5% sarcosine LS, 0.5% sulfosuccinate DOS, and 1% T100/0.5% KCl were tested.
Sort-Term Vertical Slip Tests
A range of decontamination compositions were used to generate foams. The foams were tested for their ability to adhere to a vertical surface with minimal slippage down the surface over time. To generate the various foams, a glass frit was immersed into the decontamination compositions. Air was injected through the frit and into the solution at a pressure of 15 to 20 psi. The injection of air at this rate generated foam at a volume of approximately 6 to 8 liters/minute. The resulting foam was deposited onto a vertical marble block and the rate of slippage was determined after 3 minutes. The results of the short term vertical slip tests are given in Table 2.
T100 = Triton X-100,
GLY = glycerin,
SLS = sodium lauryl sulfate,
KCL = potassium chloride,
gel = gelatin,
Ansul = Ansul Silv-Ex ™ firefighting foam additive.
Long-Term Vertical Slip Tests
The best performing decontamination compositions of Example 3 were used to generate foams for longer term testing. Again, the foams were tested for their ability to adhere to a vertical surface with minimal slippage down the surface over time. To generate the various foams, a glass frit was immersed into the decontamination compositions. Air was injected through the frit and into the solution at a pressure of 15 to 20 psi. The injection of air at this rate generated foam at a volume of approximately 6 to 8 liters/minute. The resulting foam was deposited onto a vertical marble block and the rate of slippage was determined after 30 minutes. The results of the long term vertical slip tests are given in Table 3.
Strong Acid Decontamination of Surfaces
A decontamination foam comprising 1% Ansul, 3% gelatin, and 0.5M HCl saturated with AMP and NTA was created (pH approximately 0.3). The foam was applied to test coupons (both marble and concrete) that had been contaminated with a radionuclide. The foam was allowed to remain on the coupons for 1 hour. The coupons were then brushed, water rinsed and vacuumed to remove the foam. The coupons were then tested for residual radionuclide. After 1 hour, the 1M HCl containing foam was able to remove 82% of the radionuclide from the marble coupon and 20% of the radionuclide from the concrete coupon.
Weak Acid Follow-On Decontamination of Surfaces
The coupons of Example 5 were further treated with a decontamination foam comprising 1% Ansul, 3% gelatin, and HOAc/NaOac saturated with AMP and NTA and having a pH of approximately 4.5. The foam was allowed to remain on the coupons for 4 hours. The coupons were then brushed, water rinsed and vacuumed to remove the foam. The coupons were then tested for residual radionuclide. After 1 hour, the HOAc/NaOac containing foam was able to remove and additional 6% of the radionuclide from the marble coupon (for a total of 88%) and an additional 10% of the radionuclide from the concrete coupon (for a total of 30%).
The United States Government has certain rights in this invention pursuant to Contract No. DE-AC07-05-ID14517, between the United States Department of Energy and Battelle Energy Alliance, LLC.
