Hazardous or toxic waste destruction or containment – Containment – Solidification – vitrification – or cementation
Reexamination Certificate
2001-09-14
2004-04-20
Lovering, Richard D. (Department: 1712)
Hazardous or toxic waste destruction or containment
Containment
Solidification, vitrification, or cementation
C252S186410, C510S110000, C510S370000, C510S372000, C510S504000, C516S015000, C588S253000, C588S253000, C588S901000
Reexamination Certificate
active
06723890
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to materials and methods for neutralization and decontamination of chemical and biological toxants. In particular, the present invention is directed to concentrated formulations containing solubilizing compounds and reactive compounds that can be rehydrated with water and then delivered as foams, sprays, liquids, fogs and aerosols to contaminated surfaces.
Terrorist threats, potentially involving weapons of mass destruction, are increasing both in the United States and abroad. The use, and threat of use, of chemical warfare (CW) and biological warfare (BW) agents in the context of weapons of mass destruction are of paramount concern both to national defense as well as to state and local law enforcement.
Certain CW agents known to pose a threat by terrorists share chemical characteristics that present an opportunity for the development of countermeasures. The chemical agents sarin, soman, and tabun (G-agents) are all examples of phosphorus-containing compounds which, when altered chemically, can lose their toxicity. Mustard, which is an example of the H-agents, and VX, which is an example of the V-agents, can also be altered chemically and rendered harmless. In addition, certain of the known BW agents, including botulinum toxin, anthrax and other spore-forming bacteria, vegetative bacteria, including plague, and various viruses can also be deactivated chemically.
An effective, rapid, and safe (non-toxic and non-corrosive) decontamination technology is required for the restoration of civilian facilities in the event of a domestic terrorist attack. Ideally, this technology should be applicable to a variety of scenarios such as the decontamination of open, semi-enclosed, and enclosed facilities as well as sensitive equipment. Examples of types of facilities where the decontamination formulation may be utilized include a stadium (open), an underground subway station (semi-enclosed), and an airport terminal or office building (enclosed). Many industrial applications have needs for an environmentally benign decontamination solution, including food processing plants, animal farms, hospitals, nursing homes, ambulances, etc.
The compounds that have been developed for use in detoxification of both CW and BW agents have been deployed in a variety of ways, including liquids, foams, fogs, gels, pastes, creams, and lotions. Stable aqueous foams (including “sticky” foams with glue added) have been used in various applications including fire fighting and law enforcement applications (such as prison riot containment). Such foams, however, have typically been made using anionic surfactants and anionic or nonionic polymers. These foams, unfortunately, have not been effective in the chemical decomposition and neutralization of most chemical and biological weapons (CBW) agents.
A new class of aqueous-based decontamination formulations, designated generically as “DF-100”, and a method for manufacturing DF-100, was disclosed in commonly-assigned U.S. patent application Ser. No. 09/607,586, “Formulations for Neutralization of Chemical and Biological Toxants” by Tucker and Tadros, filed Nov. 1, 2000, which is herein Incorporated by Reference. Hereinafter, that application will be referred to as the '586 application. The formulations for DF-100 have been proven effective for neutralizing both chemical and biological agents, is environmentally benign (non-toxic and non-corrosive), works on a variety of anticipated surfaces, can be rapidly deployed, requires minimal logistics support, is relatively inexpensive, and can be incorporated into a wide variety of carriers (e.g., foams, liquid sprays, fogs, mists, and aerosols).
The formulations for DF-100 comprise a cationic surfactant and a reactive compound; that when mixed with a carrier (such as water or seawater in a fluid phase) and exposed to a toxant, neutralizes the toxant. The reactive compound can be a nucleophilic or oxidizing compound or a mixture of both. Hence, the reactive compound can be both oxidizing and nucleophillic. The reactive compound can be selected from hydrogen peroxide, urea hydrogen peroxide, an activated peroxide compound (e.g., hydrogen peroxide+bicarbonate) hydroperoxycarbonate, oximates, alkoxides, aryloxides, aldehydes, peroxymonosulfate, Fenton's reagent, and sodium hypochlorite. The cationic surfactant solubilizes the sparingly soluble toxants.
A cationic hydrotrope (an ionic-surfactant-like material with short hydrocarbon segments) can be added, which increases the solubility of the toxant in aqueous media, increases subsequent reaction rates between the reactive compound and the toxant, and significantly increases the physical stability of foams made with DF-100. Increasing the foam's stability and liquid-holding power improves the overall effectiveness of neutralization of toxants by increasing the contact time of the decontamination solution with the toxant.
The formulations of DF-100 exploit the principles of cationic micelle catalysis and the solubilization power of cationic hydrotropes to dissolve the otherwise sparingly soluble toxants.
The principle for detoxifying chemical agents in the foam is to provide a mechanism to solubilize the sparingly soluble chemical (CW) agents, and to attract a nucleophilic agent, dissolved in aqueous media, to a position in close proximity to the agent molecule vulnerable to nucleophilic attack. This is accomplished through the recognition that certain nucleophilic agents are negatively charged. Therefore, the DF-100 solution contains cationic surfactants that form positively-charged micelles, which solubilize the CW agents and attract the negatively-charged nucleophiles, such as hydroxyl ions (OH
−
), hydroperoxide ions (OOH
−
), and hydroperoxycarbonate ions (HCO
4
−
). The negatively-charged nucleophiles are formed from the addition of hydrogen peroxide to the DF-100 solution, or by reacting hydrogen peroxide with a bicarbonate salt to form the highly-reactive hydroperoxycarbonate species (a much stronger oxidant).
In the aqueous environment, the CW agent is located (i.e., solubilized) within the micelle comprises of an aggregate of surfactant molecules with hydrophobic tails forming the interior core of the micelle, and hydrophilic heads concentrating at the outer surface of the micelle. These positively-charged hydrophilic heads attract the negatively-charged nucleophiles, greatly enhancing the reaction rates with the CW agents within the micelle. In this sense, the cationic surfactant acts as a catalyst to speed up the reaction between the toxant and the reactive compound. This is contrasted with the situation that would occur in a foam constructed with anionic surfactants, such as typical firefighting foam, where the negatively-charged micelles would repel the negatively-charged nucleophiles and reduce the reaction rate.
The DF-100 formulation can also contain hydrotropes, which are ionic surfactant-like molecules with short hydrocarbon segments that are added to increase the solubility of the surfactants and the CW agents. To ensure chemical compatibility, cationic hydrotropes are used. The cationic hydrotropes also contribute by significantly increasing the rate of hydrolysis of CW agents.
With respect to neutralization of BW agents, the solubilizing compounds serves to solubilize and soften the biological agent's outer coat, thereby exposing the biological agent's DNA to the reactive compound. After the solubilizing compound enhances exposure of the toxant to the reactive compound, the reactive compound reacts with the toxant, either by an oxidation or hydrolysis reaction, to neutralize the toxant. For biological agents, the solubilizing compound can be a cationic surfactant, an alcohol such as a fatty alcohol, or a cationic hydrotrope.
Depending upon the concentration of the various compounds used in the formulation of DF-100, greater than 99.999% and often as much as 99.99999% (7-log kill) or more of biological toxants (including anthrax spores) can be neutralized
Betty Rita G.
Tadros Maher E.
Tucker Mark D.
Lovering Richard D.
Sandia Corporation
Watson Robert D.
LandOfFree
Concentrated formulations and methods for neutralizing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Concentrated formulations and methods for neutralizing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Concentrated formulations and methods for neutralizing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3237876