WO2004045654A2

WO2004045654A2 - Remediating of surfaces with embedded microbial contaminant

Info

Publication number: WO2004045654A2
Application number: PCT/US2003/036212
Authority: WO
Inventors: Richard A. Hamilton; John J. Warner; Gary A. O'neill
Original assignee: Selective Micro Technologies LLC
Current assignee: Selective Micro Technologies LLC
Priority date: 2002-11-14
Filing date: 2003-11-14
Publication date: 2004-06-03
Anticipated expiration: 2005-05-14
Also published as: AU2003290924A8; AU2003295499A8; WO2004045655A3; AU2003290924A1; WO2004045654A3; AU2003295499A1; WO2004045655A2

Abstract

Disclosed are methods and apparatus for remediating embedded microbiological contaminants, e. g. , mold, fungus and bacteria. The method includes the step of exposing an embedded microbiological contaminant to a gas, e. g. , chlorine dioxide or ethylene gas, thereby remediating the microbiological contaminant.

Description

REMEDIATING EMBEDDED MICROBIOLOGICAL CONTAMINANTS

Related Applications This application claims the benefit of U.S. Provisional Patent Application Serial Nos. 60/426,630, filed November 14, 2002, and 60/449,245 filed February 20, 2003, the entire disclosures of which are hereby incorporated by reference.

Field of the Invention The present invention generally relates to a method and apparatus for remediating an embedded microbiological contaminant by exposing the embedded microbiological contaminant to a gas such as chlorine dioxide gas.

Background of the invention Surface treatments for microbiological contaminants are known and generally are only effective for treating contaminants present on an exterior surface being treated. More problematic is the treatment of embedded microbiological contaminants, which are present on interstitial surfaces and out of the reach of conventional treatments. Illustrative of this problem is the difficulty in treating mold embedded, e.g., in porous surfaces such as drywall and grout.

Mold spores are nearly everywhere. However, only under the proper temperature and humidity conditions do the spores become active and form the common surface mold with which most people are familiar. Bathrooms, showers, kitchens, basements, locker rooms, and aquatic facilities are common places to find mold growth. Mold growth on nonporous surfaces such as a fiberglass shower stall is relatively easy to treat. Commonly available surface fungicides are fairly effective at killing surface molds. When embedded mold growth occurs, however, such as in the interstitial spaces defined by drywall, plaster, concrete, wallpaper, grout, or silicone caulking, the problem can become much more complicated because the mold can grow on the surface of the porous structure out of reach of conventional treatments. As long as an oxygen and water vapor path is available, these embedded molds can flourish within the porous structure. Conventional fungicides are ineffective against embedded mpld because they cannot penetrate the relatively fine porous structure in order to access embedded molds and mold spores. Summary of the Invention The present invention provides a novel method for remediating embedded biological contaminants by administration of a gas, e.g., chlorine dioxide. The invention is based, in part, on the discovery that gas, e.g., chlorine dioxide, administered in accordance with the present invention can penetrate interstitial spaces (e.g., in drywall and grout), that conventional treatments cannot and thereby remediate the microbiological contaminant.

The present invention features a method for remediating an embedded microbiological contaminant. The method generally includes exposing an embedded microbiological contaminant to a gas to remediate the microbiological contaminant. The gas, preferably includes chlorine dioxide, sulfur dioxide, ethylene, and/or ethylene oxide. In one embodiment, the microbiological contaminant is embedded in a porous surface. In another embodiment, the microbiological contaminant is embedded in a textured surface. The microbiological contaminant can include a mold, a fungus, a bacterium, and/or a virus. In certain embodiments, the method can include exposing the embedded microbiological contaminant to a chlorine dioxide gas at a concentration between about 0.1 ppm and 1000 ppm, preferably between about 0.5 and 700 ppm, and more preferably between about 0.1 and 100 ppm by volume. All concentrations herein given in units of parts per million (ppm) are ppm by volume, unless otherwise specified. The method can include the step of generating the gas from a reactant disposed in an apparatus adhered to a surface with the embedded microbiological contaminant. The apparatus may include a pouch disposed about the reactant. The pouch can include a water vapor selective layer and/or a selective transmission film adjacent the surface with the embedded microbiological contaminant. In some embodiments, the pouch can include an impermeable layer disposed opposite the surface with the embedded microbiological contaminant. The pouch can further include an adhesive about its perimeter and facing the surface with the embedded microbiological contaminant. In some embodiments, a frangible pouch containing an initiating agent is disposed in the pouch. The method can include cleaning, sanitizing, deodorizing, sterilizing, or killing target microbiological contaminants. In one embodiment, the remediating includes killing an embedded mold spore population and/or an embedded mold population. The embedded microbiological contaminant can be embedded in a portion of drywall and/or a portion of grout. The method can include remediating an embedded microbiological contaminant in a bathroom, kitchen, restaurant, gym, medical facility, dental office, locker room, or aquatic facility. In one embodiment, the method includes the step of sealing off a room prior to exposing the embedded microbiological contaminant to the gas. The method can also include the step of dispersing the gas in a gas dispersion device, which can include, e.g., a fogger, a spray bottle, an atomizer, or a humidifier.

The invention also features an apparatus for remediating an embedded microbiological contaminant. The apparatus generally includes a reactant that generates a gas that remediates the embedded microbiological contaminant. The reactant is enclosed, at least in part, by a permeable layer. In one embodiment, the reactant is disposed in a pouch comprising the permeable layer, e.g., a water vapor selective layer or a selective transmission film. Additionally or alternatively, the pouch can include an impermeable layer disposed opposite the permeable layer. The reactant can include an aqueous soluble acid and an aqueous soluble chlorite. In one embodiment, the apparatus includes an initiating agent disposed in a frangible pouch.

In a preferred embodiment, the apparatus includes an adhesive strip disposed about its perimeter. Additionally or alternatively, the apparatus can be in the form of a strip for application a surface including the embedded microbiological contaminant. In another embodiment, the apparatus can also include a dispersion device for dispersing the gas, e.g., a fogger, a spray bottle, an atomizer, or a humidifier. In any of these embodiments, the gas preferably includes chlorine dioxide, sulfur dioxide, ethylene and/or ethylene oxide.

The invention also includes kits that include any of the apparatus described herein.

Description of the Drawings The invention is pointed out with particularity in the appended claims. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. The advantages of the invention are described herein, as well as further advantages of the invention, can be understood by references to the description taken in conjunction with the accompanying drawings.

Figure 1 A and IB are a top view and cross-sectional side view, respectively, of an exemplary apparatus that includes an adhesive pouch. Figures 2A and 2B are an exploded side view and a cross-sectional perspective view of an exemplary apparatus that includes a frangible pouch.

Figures 2C and 2D are cross-section perspective views of two further embodiments of exemplary apparatus that include a frangible pouch. Figures 3 A and 3B are an exploded view and a cross-sectional perspective view, respectively, of an exemplary apparatus that includes a partitioned sachet.

Figure 4 is a perspective view of an exemplary apparatus that includes a dispersion device.

Figure 5 is a perspective view of an exemplary apparatus that includes a housing for a fluid dispersion system.

Figure 6 is a perspective view of an exemplary apparatus that includes another dispersion device.

Figures 7A and 7B are a perspective view and cross-sectional side view, respectively, of another embodiment an exemplary apparatus that includes an adhesive strip.

Figure 8 is a cross-sectional side view of an exemplary apparatus that includes a ClO₂ releasing apparatus.

Figures 9 A and 9B are photographs of surfaces subjected to the mold remediation methods and apparatus of the invention.

Detailed Description of the Invention In order to more clearly and concisely describe the subject matter of the claims, the following definitions are intended to provide guidance as to the meaning of specific terms used in the following written description, examples and appended claims. As used herein, the term "microbiological contaminants" refers to any microbial contaminant. Example of microbiological contaminants include, but are not limited to, fungi, bacteria, viruses, protista, and molds, including mold spores. Examples of such microbiological contaminants include Stachybotrys Chartarum, Aspergillus niger, Absidia sp., Acrodontium salmoneum, Aspergillus candidus, anthrax, etc. As used herein, the term "embedded microbiological contaminants" refers to microbiological contaminants that are disposed in an interstice or space between bodies closely set, or between parts that compose a body. Microbiological contaminants present in the spaces defined by textured surface, pores, crevices or other types of voids are examples of embedded microbiological contaminants.

The term "porous surface" refers to a surface of a structure having multiple pore interstices. Examples of porous surfaces include, but are not limited to, tile grout, plaster, drywall, ceramic, cement, clay, bricks, stucco, and plastic.

The term "textured surface" refers to a surface having multiple interstices imparted to it, typically, for a desired visual effect. Examples of textured surfaces include, but are not limited to, wallpaper, fabric, tiles, cement, and vinyl flooring.

Other types of voids where embedded microbiological contaminant can be found include, but are not limited to, interstices defined by heating and/or cooling fins, filters, vanes, baffles, vents, crevices in walls or ceilings, paper and wood products such as lumber, paper, and cardboard, woven products such as blankets, clothing, carpets, drapery and the like.

As used herein "pouch" refers to a hollow receptacle defining a reaction volume. The pouch is "closed" in the sense that the reactants are substantially retained within the pouch and the pouch volume is substantially sealed around its perimeter. However, the material or materials used to construct the pouch are chosen to allow exit of the gas generated, and optionally, entry of the initiating agent. A pouch can be a sachet, an envelope or a receptacle defining a puncturable surface. As used herein a "puncturable surface" means a surface that may be pierced or punctured when a force is applied to the surface. A puncturable surface may include any material that retains a puncture hole where it was punctured. Alternatively, a puncturable surface may include any material that retracts or contracts to an unpierced (e.g., a closed) configuration after being punctured (e.g., by a needle). Another example of a puncturable surface is a frangible surface that ruptures upon application of pressure, e.g., by actuation of a second vessel against the puncturable surface, thereby allowing the second vessel to engage the first vessel.

As used herein, "frangible pouch" is a pouch that ruptures when pressure is applied to it. Preferably, the frangible material is constructed from a multi-layer plastic, e.g., polyolefin material, having a weak layer positioned near the sealing surface that will fail under pressure. A frangible pouch, also known as an ampoule, can also feature an initiating agent within the frangible pouch, and a sock disposed about the frangible pouch. The sock can be constructed from any material that does not impede the passage of initiating agent out of it and that substantially retains the frangible pouch after it is disrupted. The sock is optional, but desirable when the frangible pouch is constructed of brittle materials, e.g., brittle plastic or glass, so that the frangible pouch pieces are substantially retained within the sock. Examples of sock materials suitable for use in accordance with the present invention are meshes made from polymers or natural fibers such as cotton or cellulose, or non-wovens such as TYNEK® non-woven materials made by DuPont Company (Wilmington, DE) or the non-woven materials sold by Marubeni Corporation (Tokyo, Japan).

As used herein the term "sachet" means a closed receptacle for reactant. The sachet is "closed" in the sense that the reactants are substantially retained within the sachet and the sachet volume is substantially sealed around its perimeter. However, the material or materials used to construct the sachet are chosen to allow exit of the gas generated, and optionally, entry of the initiating agent. The material or materials used to construct sachets are referred to herein as "sachet layers." Sachet layers typically are constructed from a planar material, such as, but not limited to, a polymeric sheet or film. Preferred materials for sachet layers are described in greater detail below. Relying upon the teachings disclosed herein, and the general knowledge in the art, the practitioner of ordinary skill will require only routine experimentation to identify one or more sachet layers and/or construct one or more sachets adapted for the purpose at hand. Sachets can include more than one material, e.g., a sachet can comprise a barrier layer and sachet layer sealed about the perimeters of the layers to define a closed receptacle for reactant. Another example of a sachet is a rigid frame defining one or more openings and one or more layers, including at least one sachet layer, disposed about the one or more openings to define a closed receptacle for reactant. The term "envelope" refers to a closed receptacle wherein the envelope volume is sealed substantially about its perimeter, which contains at least one sachet and allows release of the gas from the envelope. The material or materials used to construct envelopes are referred to herein as "envelope layers." Envelope layers typically comprise a planar material such as a sheet or film, including, but not limited to perforated films, non-perforated films and membranes. Preferred materials for envelope layers are described in greater detail below. Relying upon the teaching disclosed herein, and the general knowledge in the art, the practitioner of ordinary skill will require only routine experimentation to identify one or more envelope layers and/or construct one or more envelopes adapted for the purpose at hand.

"Permeable layer," as used herein, refers to a layer that permits passage of gas generated by an apparatus of the present invention. Permeable layers typically are constructed from polymeric materials. "Impermeable layer," as used herein, refers to a layer that substantially prevents or hinders passage of initiating agent and the generated gas. As contemplated herein, the impermeable layer does not participate in the generation of gas in that it does not facilitate contact between initiating agent and reactant, but it does function to direct generated gas to the area to be remediated. Impermeable layers can be constructed from various materials, including polymeric material, glass, metal, metallized polymeric material and/or coated papers. As used herein, barrier layers are impermeable layers.

The skilled artisan will appreciate that what is considered to be an "impermeable layer" and what is considered to be a "permeable layer" is defined relative to the transmission rates of the respective layers used to construct apparatus of the present invention and the desired shelf life of the product. Relying upon the teachings disclosed herein, and the general knowledge in the art, the practitioner of ordinary skill will require only routine experimentation to identify and/or construct one or more impermeable layers and one or more permeable layers adapted for the purpose at hand. "Selective transmission films" are films that are neither perforated nor porous, but instead transfer gases through the polymer structure of the film. Selective transmission films are multilayered or mixed polymer materials, where the layers and the polymers are chosen for controlled transmission of gases, such as carbon dioxide and oxygen. Selective transmission films are preferred in dry applications because they allow the gas to diffuse out of the apparatus. Further, such layers also can be employed to retain the initiating agent once released from a frangible pouch. Moreover, the selective transmission film can increase the stability of the apparatus prior to its use because it does not readily allow ambient water to diffuse into the apparatus, which could prematurely initiate the reactants. As used herein "water vapor selective" refers to a material that selectively allows permeation of water vapor and substantially impedes permeation of liquid water. More preferably, the material excludes permeation of liquid water. Typically, the water vapor selective material is hydrophobic. The skilled practitioner typically refers to water vapor selective material as water impermeable, although water vapor can permeate the layer, and refers to materials that allow permeation of liquid water as water permeable. Suitable water vapor selective materials can be made from a variety of materials includmg, but not limited to, polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene (PE), and fluorinated ethylene propylene (FEP). Some water vapor selective materials are applied to a web that provides structural integrity to the material, e.g., where the material is tliin and requires support to prevent tearing during manufacture and use.

As used herein "reactant" refers to a reactant or a mixture of reactants that generate gas in the presence of an initiating agent. Such reactants include, but are not limited to metal chlorites (e.g., sodium chlorite), and acids (e.g., citric acid). The reactant or reactants can further include additives, such as activated hydrotalcite. As used herein "initiating agent" refers to any agent that initiates the generation of gas from the reactant. For purposes of the present invention, initiating agent includes, but is not limited to, gaseous or liquid water. The initiating agent can enter the apparatus through the sachet layer. For example, for dry biocidal applications of the present invention, such as for the reduction of molds, moisture in the atmosphere can be used as an initiating agent. Alternatively, the initiating agent can be included within the apparatus, e.g., contained in a second vessel that is coupled with the first vessel. Yet another alternative for initiation is for the apparatus to be dipped or immersed in water or aqueous media, or otherwise wetted, e.g., with a wet sponge.

Examples and embodiments of the materials and apparatuses described herein are also disclosed in U.S. Patent Nos. 6,607,696 and 6,602,466, as well as PCT Publication No. WO 03/05146, all entitled "Methods and Apparatus for Controlled Release of a Gas," the entire disclosures of which are incorporated in their entirety by this reference.

Generation of a gas, e.g., by acid activation, is well known in the art. For example, chlorine dioxide (ClO₂) is generated from sodium chlorite and an acid, such as citric acid, in the presence of moisture. Alternatively, chlorine dioxide can be produced by the reduction of a chlorate, e.g., sodium chlorate or potassium chlorate, in the presence of an acid, e.g., oxalic acid. Another example of generation of a gas by acid activation is the activation of a sulfite, e.g., sodium bisulfite or potassium bisulfite, with an acid, e.g., fumaric acid and/or potassium bitartrate, in the presence of moisture to form sulfur dioxide. Yet another example is the acid activation of a carbonate, e.g., calcium carbonate with an acid, e.g., citric acid, to form carbon dioxide.

Other applications will be apparent to the skilled practitioner. For example, the generation of nitrogen dioxide by the acid activation of a nitrite, e.g. , sodium nitrite or potassium nitrite. Alternative routes for generation of a gas, e.g., reduction of chlorates by sulfur dioxide (Mathieson Process) are well known in the art and can be utilized in accordance with the present invention.

In one aspect, the present invention provides a method for remediating an embedded microbiological contaminant. The method generally includes the step of exposing an embedded microbiological contaminant to a gas, e.g. chlorine dioxide, sulfur dioxide, ethylene, or ethylene oxide, thereby remediating the microbiological contaminant.

In one embodiment, the microbiological contaminant is embedded in a porous surface, such as tile grout, plaster, drywall, ceramic, cement, clay, bricks, stucco, caulking, heating, ventilating, and air conditioning (HNAC) system ducting, ductwork, insulation, and plastic. Additionally or alternatively, the microbiological contaminant is embedded in a textured surface. Examples of textured surfaces are wallpaper, fabric, tiles, cement, and vinyl flooring. The microbiological contaminant can also be embedded in other types of interstices or voids. Examples of such interstices include those defined by heating and/or cooling fins, filters, vanes, baffles, vents, crevices in walls or ceilings, paper and wood products such as lumber, paper, and cardboard, woven products such as blankets, clothing, carpets, drapery, insulation, ceiling tiles, floor coverings, HNAC system, ductwork, insulation and the like.

The microbiological contaminants can include a mold, mildew, a bacterium, a fungus and/or a virus, e.g. Aspergillus-niger, stachybotrys, and penicillin digitatum. h one embodiment, the gas includes or consists of ClO₂ gas, and its concentration at the contaminant is between about 0.1 ppm and about 1000 ppm, preferably between about 0.5 ppm and 700 ppm, and most preferably between about 0.1 ppm and about 100 ppm. It is to be understood that all values and ranges within the ranges described above are encompassed by the present invention. The remediation encompassed by the present invention can include cleaning, sanitizing, deodorizing, sterilizing, or killing target microbiological contaminants. This remediation can include killing an embedded mold spore population and/or an embedded mold population. The embedded microbiological contaminant can be embedded, e.g., in a portion of drywall and/or a portion of grout. The method can include remediating one or more embedded microbiological contaminants in a bathroom, kitchen, restaurant, gym, medical facility, dental office, locker room, or aquatic facility.

In a further embodiment, the method includes spraying or otherwise delivering a gas (e.g., ClO₂) onto or into a contaminated surface or environment. The spray can be, for example, a 5% to 99% mist, a 10% to 90% mist, or preferably a 60 % to 70 % mist containing a gas such as ClO₂. The sprayer can include a variety of spray systems such as high volume sprayers, low volume sprayers, aerosol sprayers, thermal pulse-jet foggers, mechanical aerosol generators, cold foggers, air assisted electrostatic sprayers, air-assisted rotary mist applicators, nebulizers, atomizers, or others known in the art. Other delivery devices and methods can be used, e.g., the use of compressed gas (e.g., nitrogen) can be used to sparge chlorine dioxide gas from a liquid solution.

In another embodiment, the method can include sealing off a perimeter of the surface with the microbiological contaminant, such that the gas, e.g., ClO gas, generated is substantially retained within the sealed perimeter. This embodiment can include sealing off, e.g., a wall or portion of a wall with plastic. Sealing off a perimeter for treatment can also include providing a gas generating apparatus with adhesive about its perimeter and affixing it directly to the surface to be treated. Preferably, in this embodiment, the outer layer of the apparatus (the surface opposite the surface facing the wall), is impermeable, such that the gas is retained in the space bounded by the impermeable layer and the adhesive.

In one embodiment, the method includes the steps of sealing off a room or building prior to exposing the embedded microbiological contaminant to the gas, and dispersing the gas in a gas dispersion device. The room can be sealed off, e.g., by sealing the windows and doors with plastic as well as ducts, etc. Sealing off the room retains the gas at a high concentration in the room for a desired time period. Sealing off the room also protects workers in the area from exposure to unrecommended levels of gas. Sealing off can include shutting the doors and windows. The apparatus can further include a gas dispersion device, such as a fogger, a spray bottle, an atomizer, a nebulizer, a sprayer system, an aerosol system, a sparging device or a humidifier. Various apparatus can be employed in accordance with the methods of the present invention including, but not limited to, the exemplary apparatus described herein. Generally, by using discrete amounts of reactant disposed within an apparatus such as a pouch, the skilled practitioner can fabricate a gas delivery apparatus that disinfects a target area. The apparatus can be affixed (e.g., with an adhesive strip or other fastening device), to the surface to expose the microbial contaminants to the gas. The present invention can be used for a variety of applications, including delivery of a gas to residential and commercial surfaces, and for a variety of purposes including, but not limited to disinfecting, deodorizing, bleaching, sanitizing, and sterilizing.

The current invention overcomes the shortcomings of conventional surface fungicides and other microbial treatments. In one embodiment, the reactant is substantially sealed in a pouch (e.g., a sachet), that includes a gas permeable layer. The gas permeable layer can be any permeable layer, e.g., a water vapor selective material or any of the permeable layers described herein. The sachet or pouch can wholly be constructed from gas permeable layers, or the gas permeable layer can comprise only a portion, e.g., one side of a sachet. The remainder of the sachet or pouch can include impermeable materials or other materials, such as sachet layers. The apparatus can after include additional elements such as additional sachets or one or more envelopes. A portion of a surface to be treated can be sealed off to concentrate the gas generated in the sealed area. The portion sealed can be, e.g., a wall, bathroom stall, a room, a truck, a house, or an office building. There are many advantages to this aspect of the invention. For example, if drywall or plaster walls become contaminated with embedded mold, the only effective current means to treat the problem is to remove the contaminated panels and rebuild the surface. Not only is this option expensive and time consuming; it can expose workers to potentially harmful molds. The present invention allows for the possibility of effectively killing embedded mold with a convenient and safe method. The apparatus can be in the form of a surface patch that generates a gas (e.g., chlorine dioxide gas), which diffuses across a permeable membrane (e.g., a water vapor selective layer), and migrates into the porous surface killing the embedded microbe (e.g., mold and/or mold spores). In one embodiment, the patch includes an impermeable layer on the side of the apparatus to be placed opposite the surface to be treated. The utilization of an impermeable backing prevents the escape of the gas in the opposite direction, instead focusing diffusion to the surface containing the microbial contaminant. The patch can also include an adhesive layer that faces the contaminated surface. The adhesive or other attachment means can be applied about the entire perimeter or only a portion of the perimeter. Other methods and devices for adhering an apparatus to a surface can also be employed, such as one or more clips, velcro, etc.

In a preferred embodiment, the present invention features an apparatus for the generation of gas (e.g., ClO₂), that is applied to dry wall. However, the present invention can be applied to any number of porous surfaces which may be found, but not limited to, the home, gym, dental and medical equipment, building restoration, food processing plants, and any other areas which would have a surface (e.g., a porous or textured surface), containing an embedded contaminant.

In one embodiment, the reactant includes a mixture of a chlorite salt and an organic acid. The various apparatus of the invention can further include an initiating agent (e.g., water), preferably contained in a frangible pouch or ampoule. Such a pouch or ampoule can be constructed from materials that allow for manual rupture, e.g., fragile plastics or glass or materials with a weak seal. Generation of gas could then be initiated by rupturing the pouch or ampoule and thereby releasing the initiating agents. Chlorine dioxide thus generated can then diffuse across the permeable membrane and into the contaminated surface targeting the microbiological contaminant.

Further embodiments include apparatus in the form of a strip for application to selected surfaces and apparatus that include dispersion devices for application in larger areas, e.g., a room or a portion of a room. Examples of various embodiments of the present invention are now described.

Figure 1A depicts an exemplary embodiment of an apparatus of the present invention, where an adhesive patch 10 is constructed of an impermeable layer 20 and permeable layer 30 sealed together about their perimeter 40 to form a pouch. Within this sealed perimeter is a mixture of a chlorite salt and organic acid 50. Also, within the perimeter is an optional frangible pouch 60 containing an initiating agent 70. At the perimeter of the pouch, a mechanism 80 is fashioned such that it provides a means of adhering to a porous surface. This mechanism can be an adhesive bond, tape, drywall bond, or other means of adhering. The pouch can be dimensioned for the particular application, e.g., for application to an area or a portion of an area having microbial contaminants. Figure IB is a side view of the previously described embodiment that further illustrates the use of impermeable and permeable layers. This "single-sided" feature helps control the direction 90 and rate of the chlorine dioxide being administered. Optionally, the apparatus can contain further sachet and or envelope layers. The apparatus can also include a permeable barrier layer adjacent to the sachet layers that prevents premature initiation of the reactant and that can be removed prior to use.

In another embodiment, reactants are retained with a sachet constructed from a material that allows escape of the gas from the sachet. Preferably, the sachet is constructed from hydrophobic and/or water vapor selective material, however, any of the materials described herein can be used to construct the sachet. The sachet can further include a frangible pouch or ampoule containing initiating agent.

In a still further variation of this embodiment, the chlorine dioxide gas generating apparatus may be placed within an envelope. One function of the envelope is to control the influx of the initiating agent, while limiting the diffusion of the reactants from the sachet to the surrounding fluid, be it gaseous or liquid. The envelope also allows the gas to diffuse to the surrounding fluid, be it gaseous or liquid. By limiting the transmission of the initiating agent into the apparatus and limiting and/or preventing diffusion of the reactant out of the apparatus, the reactant remains concentrated and the pH of the reactive system is localized within the apparatus to optimize the conversion of reactant to gas. Additionally, intermediates and/or by-products of reaction, e.g. water, also can contribute to the efficiency and/or duration of the reaction by its affect on the equilibrium of the reactions. Figures 2 A and 2B depict another exemplary apparatus 210 constructed in accordance with the present invention. Apparatus 210 includes first sachet 232, first reactant 242 disposed within first sachet 232, second sachet 234, second reactant 244 disposed within second sachet 234, third sachet 250 disposed about first sachet 232 and second sachet 234, and envelope 220 disposed about third sachet 250. Disposed within the envelope 220 adjacent to the third sachet 250 is frangible pouch 260, and initiating agent 264 disposed within frangible pouch 260. Apparatus 210 is particularly useful for the delivery of gas in a dry application because initiating agent 264 is contained within the apparatus 210. In this embodiment, first reactant 242 and second reactant 244 generate a gas in the presence of initiating agent 264. For this to occur, frangible pouch 260 is ruptured, e.g., by exerting pressure on frangible pouch 260 so that initiating agent 264 is delivered into first envelope 220. Third sachet 250 allows contact of initiating agent 264 with first sachet 232 and second sachet 242.

In one embodiment, the first sachet and the second sachet may be constructed from a hydrophilic material having a pore size between about 3 microns and 5 microns. A suitable material is a 3 micron pore Nylon 6,6 material sold under the trade designation BIODYNE A by Pall (Port Washington, NY). A suitable third sachet layer is 0.65 micron pore hydrophobic polypropylene membrane, such as that sold under the trade designation DOHP by Millipore (Bedford, MA). The third sachet limits the diffusion of reactant out of the third sachet and thus, it keeps the reactant concentrated within the third sachet and the pH localized. Preferably, the third sachet volume is less than 4 times that of the first reactant and the second reactant combined, and most preferably less than 2 times that of the first reactant and the second reactant combined.

Preferably, envelope 220 is constructed from a selective transmission film. Selective transmission films are preferred in dry applications because it allows the gas to diffuse out of the envelope, while retaining the initiating agent once released from the frangible pouch. Moreover, the selective transmission film increases the stability of the apparatus prior to its use because it does not easily allow ambient water to diffuse into the apparatus, which could prematurely initiate the reactants. Furthermore, keeping the reactant, e.g., sodium chlorite and acid, separated into two sachets also can increase the stability of the apparatus because it retards initiation in the event that the initiating agent diffuses into the apparatus prior to rupturing the frangible pouch. One suitable selective transmission film is a multilayered polymer film having a carbon dioxide transmission rate of 21,000 cc/m²/24hrs and an oxygen transmission rate of 7,000 cc/m²/24hrs sold under the trade designation PD-961 Cryovac® selective transmission film from Sealed Air Corporation (Duncan, SC).

Frangible pouch 260 can be constructed of any material that ruptures when pressure is applied to it. Preferably, the frangible pouch is constructed from a multilayer plastic, e.g., polyolefin material, having a weak layer positioned near the sealing surface that will fail under pressure. Initiating agent 264 can be any agent that initiates a gas-generating reaction, e.g., water. Preferably the initiating agent is water or an aqueous solution, but is not limited thereto.

Figures 2C and 2D depict variations of the previously described variations. For example, Figure 2C includes first sachet 232, first reactant 242 disposed within first sachet 232, second sachet 234, second reactant 244 disposed within second sachet 234, initiating agent 264 disposed within frangible pouch 260, third sachet 250 disposed about first sachet 232, second sachet 234, and envelope 220 disposed about third sachet 250. In still a further example, Figure 2D includes first sachet 232, first reactant 242 disposed within first sachet 232, second sachet 234, second reactant 244 disposed in second sachet 234, initiating agent 264 disposed within frangible pouch 260, and third sachet 250 disposed about first sachet 232, second sachet 234, and frangible pouch 260. The skilled practitioner will appreciate that the first reactant and the second reactant may be combined and disposed in a single sachet, i.e., first sachet and second sachet can be combined into a single sachet. Moreover, the initiating agent disposed in frangible pouch can be disposed within the volume defined by the third sachet. The skilled practitioner will also appreciate that one reactant may be disposed in a first sachet, and a second reactant can be loose in a further sachet and/or envelope. For example, a first reactant (e.g., citric acid) can be contained in a sachet, and the sachet and a second reactant (e.g., chlorite) can be disposed in an envelope or a second sachet. Figures 3 A and 3B depict still yet another exemplary apparatus 310 constructed in accordance with the present invention. In general overview, apparatus 10 includes sachet 370 and partition 380 disposed within sachet 370 defining first volume 382 and second volume 384 within sachet 370. Also shown is first reactant 342 disposed within first volume 382 and second reactant 344 disposed within second volume 384. In this embodiment, first reactant 342 and second reactant 344 generate a gas in the presence of an initiating agent, and sachet 370 allows entry of an initiating agent into apparatus 310. Preferably, sachet 370 is constructed using a hydrophobic membrane to control entry of the initiating agent into the apparatus. Preferably, partition 380 is constructed using hydrophilic membrane so that the initiating agent, once within the apparatus, will migrate to partition 380. If, for example, first reactant 342 is sodium chlorite and second reactant 344 is citric acid, reaction begins when an initiating agent reaches partition 380. In a preferred embodiment, sachet 370 is constructed from 0.65 micron pore hydrophobic polypropylene membrane, such as that sold under the trade designation DOHP by Millipore (Bedford, MA), and partition 380 is constructed from 0.65 micron pore hydrophilic polypropylene membrane, such as that sold under the designation MPLC by Millipore (Bedford, MA).

Optionally, the apparatus depicted in Figures 3A and 3B may further comprise an envelope (not shown) enclosing the sachet. In one embodiment, the envelope is constructed from a selective transmission film, such as the PD-961 Cryovac® selective transmission film from Sealed Air Corporation (Duncan, SC). Additionally, the apparatus can further comprise a frangible pouch and an initiating agent disposed within the frangible pouch, disposed within the envelope.

Figure 4 depicts an exemplary embodiment of a fluid dispersion system 1800 constructed in accordance with the present invention. The fluid dispersion system 1800 includes a fluid dispersion apparatus 1810 and a gas delivery apparatus 1820. The gas delivery apparatus 1820 includes a sachet 1830 and a reactant 1840 disposed in the volume defined by the sachet 1830 that generates gas in the presence of an initiating agent. In this embodiment the fluid dispersion apparatus 1810 is a humidifier and the sachet is disposed in a fluid reservoir 1845. The reservoir contains a fluid 1850 that includes an initiating agent. Alternatively, the sachet can be disposed in a dispersion outlet.

The gas delivery apparatus 1820 can be any of the gas delivery apparatus described herein. For example, the sachet 1830 can comprise two adjacent sachet layers, a barrier layer adjacent a sachet layer, or a rigid frame defining an opening and a sachet layer disposed about the opening. The apparatus 1820 can also include further sachets, one or more envelope and/or envelope layers, further reactants, and additives, such as stabilizers and desiccants (not shown). The sachet can be affixed within the fluid dispersion apparatus by mechanical means, can float freely in the fluid reservoir, or it can include a weight or be constructed from material such that the sachet sinks to the bottom of the reservoir as shown in Figure 4. The fluid dispersion apparatus 1810 includes a means of atomizing the fluid

1858, and an opening 1854 through which the atomized fluid containing the gas exits the fluid dispersion apparatus 1810. Means for atomizing fluids are well known. The fluid dispersion 1810 apparatus can be any fluid dispersion apparatus known in the art. The fluid dispersion apparatus can disperse fluid by any means, including mechanical means, sonication, atomization, nebulization, and/or vaporization. Many such fluid dispersion apparatus suitable for use with the present invention are readily available commercially as well as to consumers, for example, DURACRAFT™ Cool Mist™ humidifiers from KAZ Home Environments (Southborough, MA), which draws liquid into a rapidly spinning wheel with small openings and disperses atomized fluid into the environment. Also suitable are apparatus that disperse fluid by passing air over a wick that is in contact with a liquid such as the Cool Moisture™ Humidifier made by KAZ Home Environments (Southborough, MA). Further fluid dispersion apparatus can include dispersion conduits and devices, e.g., wand sprayers, pump sprayers or others known in the art.

In another aspect of the present invention, the fluid dispersion system can include a housing that contains a gas delivery apparatus. The housing can be placed or affixed to a fluid dispersion apparatus outlet so that fluid exiting the fluid dispersion apparatus passes through the gas delivery apparatus so that gas and fluid exit the housing and enter the environment.

Figure 5 depicts a housing for use with a fluid dispersion system in accordance with the present invention. The housing 1900 can be attached, e.g., to the fluid dispersion apparatus 1810 depicted in Figure 4. The housing 1900 defines an opening 1910 defined by the housing for fluid dispersed by the fluid dispersion apparatus, and openings 1914, for expelling gas and fluid. Disposed in the housing 1900 is a sachet 1930 and a reactant 1940 disposed in the volume defined by the sachet that generates gas in the presence of an initiating agent. The housing 1900 can be attached to the fluid outlet of any fluid dispersion apparatus and the sachet 1930 can be used instead of or in addition to a sachet in the dispersion apparatus reservoir as depicted in Figure 4.

Figure 6 depicts another exemplary embodiment of a fluid dispersion system 2000 constructed in accordance with the present invention. The fluid dispersion system 2000 includes a fluid dispersion apparatus 2010, a housing 2020, and a gas delivery apparatus 2030. The gas delivery apparatus 2030 includes a sachet 2034 and a reactant 2038 disposed in the volume defined by the sachet that generates gas in the presence of an initiating agent. In this embodiment the fluid dispersion apparatus 2000 is a humidifier and the sachet 2034 is disposed in the housing 2020. The reservoir contains a fluid 2040 that includes an initiating agent.

The fluid dispersion apparatus 2010 includes a means of atomizing the fluid 2044, and an opening 2048 through which the atomized fluid containing the gas exits the fluid dispersion apparatus 2010 and enters the housing 2020. The housing 2020 defines openings 2050 that allow exit of the gas and the atomized fluid from the housing 2020.

The gas delivery apparatus 2030 is disposed within the housing and can be attached or affixed to the housing. The sachet includes a rigid frame 2054 defining a first opening 2056 and a second opening 2058. The sachet further includes a first sachet layer 2060 and a second sachet layer 2064 disposed about the first opening 2056 and the second opening 2058, respectively. The sachet can be affixed or removably attached to the housing by any known means (not shown), e.g., a snap fit.

Alternatively, the gas delivery apparatus 2030 can be any of the gas delivery embodiments described herein. For example, the gas delivery apparatus can further include additional sachets, sachet layers, envelope layers, envelopes, additional reactant and/or additives as described herein. The gas dispersion apparatus can be any gas dispersion apparatus including those described above.

The fluid dispersion system described herein can be used to reduce or eliminate biological contaminants in a porous surface by utilizing the fluid dispersion apparatus, e.g. water in a humidifier or vaporizer. Additionally or alternatively, the system can be used to disperse chlorine dioxide gas and/or other gases into the environment to destroy or mask odor-causing compounds, e.g., mold or mold spores.

Figure 7A and 7B depicts another exemplary apparatus 2100 of the present invention that generally includes reactant 2170 disposed in sachet 2120, and an adhesive device 2110. The apparatus 2100 can be applied with adhesive device 2110 to porous surfaces, e.g., grout which contain biological contaminant. The sachet 2120 has two sides 2140, 2150. Each side can be constructed from the same or different materials and can include further layers (not shown). For example, the apparatus 2100 can have a directionality by constructing the sachet 2120 from a permeable material one side 2140 and an impermeable material on side 2150. The sachet 2120 can include a further, removable impermeable material disposed adjacent to the permeable material for removal prior to use (to prevent premature initiation of the reactant). The sachet 2120 could further include other layers such as envelope layers and the like.

Figure 8 depicts yet another exemplary apparatus 2200 for use in accordance with the present invention. Apparatus 2200 can be employed to generate gas (e.g., chlorine gas), by engaging the frangible pouch 2240, with structural feature 2270.

Structure feature 2270 can be threaded for threaded engagement with the female portion 2210 of apparatus 2200 as shown or can be otherwise configured for a snap fit, friction fit, or engagement by any other known means. Engaging feature 2270 with the frangible pouch causes initiating agent 2250 to come into contact with reactant 2260. Gas generated exits the apparatus through permeable layer 2280. Further additional layers could be positioned adjacent to permeable layer 2280 to control the rate of gas released, limit the exit of reactants or byproduct, and/or to prevent premature initiation (e.g., by including a permeable layer for removal prior to engagement. This embodiment could be a portable apparatus that sits on a base 2230 or could be placed on a wall by a hanging device (not shown). This particular embodiment could be utilized for delivering lower concentration of chlorine dioxide gas and be used for prevention of biological contaminants, e.g., mold spores and mold.

In another aspect of the invention, the apparatus includes a sachet that includes a rigid frame defining at least one opening and a sachet layer disposed about the opening such that a volume is defined by the sachet. The rigid frame can be a rigid barrier layer. The rigid frame can take the form of a tubular member that can have any shape, such as a circular, oval, rectangular, or square-shaped cross section along the tube. If the rigid frame is tubular, at least one end preferably has a sachet layer disposed about it. A second sachet layer may be disposed about a second end of the rigid frame. Additionally or alternatively, any other layer that will define a closed receptacle for reactant, such as a barrier layer, can be disposed about a second end. Yet another option is to have a detachable member on the second end such as a threaded cap that can be removed, e.g., to remove and/or replace reactant and any additional sachets within the sachet. Sachets including rigid frames are advantageous because they can be fit into various devices, e.g., a humidifier, filter or cartridge. They also can be dropped in a reservoir and, depending on the materials used to construct the rigid frame, can sink to the bottom of a solution, e.g., if made with PNC, or float on top, e.g., if constructed with a foamed material. The apparatus can further include weighted materials to increase its tendency to reside at a bottom of a reservoir. The sachet includes one or more reactants that generate a gas in the presence of the initiating agent. The reactants can be mixed or separated by further structures, such as an additional sachet or an intermediate layer within the sachet as described herein. The rigid frame can be constructed from any rigid materials such as the barrier materials described above. For example, the rigid materials can include polyvinylchloride, polyethylene, polypropylene, polyester, styrene, polystyrene, polyethylene terephthalate, polyethylene terephthalate glycol, acrylobutylstyrene, polyacrylate, nylon, polyamide, and combinations thereof. The reactants can be any of the reactants described above. The reactants can be mixed or separated in separate volumes, e.g., sodium chlorite can be disposed in the first sachet and citric acid in the second sachet. Optionally the reactants can include additives. Preferably, one or more of the reactants is mixed with activated hydrotalcite.

The sachet layers can be constructed from any of the sachet materials described herein. For example, the sachet layers can be constructed from a water vapor selective material, e.g., a PTFE/PE layer as described above. The sachet layers can also be constructed from a layer that initially allows entry of water but subsequently impedes the passage of water. Without wishing to be bound to any particular theory, it is believed that the layer swells upon introduction of water to the layer and that the layer allows passage of water until the layer swells to such an extent that water can no longer pass through the pores. In a currently preferred embodiment, the first sachet layer is constructed from a water vapor selective material, the second sachet layer is constructed from a layer that initially allows entry of water but subsequently impedes the passage of water, and the rigid layer is injection molded PNC. The apparatus can further include additional sachet layers and/or envelope layers adjacent the first and second sachet layers. The additional sachet layers and envelope layers can be constructed of any of the materials described herein. The first and second reactant can be any of the reactants described herein. The apparatus can further include additional sachets, envelopes, and/or reactant additives, such as desiccants, stabilizers and the like as described above. While preferred, the second sachet is optional and the reactants need not be separated in any manner. A further embodiment features a method for delivering a gas by employing an axially slidable gas generating apparatus. In particular, the user aligns a first end of a second vessel with a puncturable surface of another vessel. When the user pushes the first end into the puncturable surface, the second vessel creates a hole in or raptures the puncturable surface. The second vessel slides into vessel and couples or engages with first vessel. In one embodiment, a second vessel slides axially into a first vessel. In this preferred embodiment, the second vessel is engaged with the first vessel by a pressure fit. The second vessel may be adapted to deliver reactant to the first vessel. For example, when the second vessel and the first vessel couple, the second reactant contained in the second vessel contacts the reactant contained in vessel, initiating the reaction to generate a gas. The generated gas exits apparatus through the sachet layer and optional envelope layer, and the gas is delivered to area to be treated.

In one embodiment, the second vessel twists axially into the first vessel. In this preferred embodiment, the second vessel can be engaged with the first vessel by a threaded fit. The second vessel may be adapted to deliver reactant to the first vessel. For example, when the second vessel and the first vessel couple, the second reactant contained in the second vessel contacts the first reactant contained in the first vessel, initiating the reaction to generate a gas. The generated gas exits apparatus through a sachet layer, and the gas is delivered to the area to be treated. The materials utilized to construct the apparatus of the present invention preferably are durable and stable. Preferably, the materials also are capable of fusing upon the application of heat for construction purposes, e.g., so that the material can be fused about its perimeter to form, e.g., a pouch, sachet or envelope. The apparatus can be constructed with various materials, including polymeric materials or layers, such as perforated films and membranes.

Layers used can be chosen to limit or eliminate the diffusion of the reactants out of the apparatus, control the rate of gas released from the apparatus and control the initiation of the reactants. For example, a hydrophilic layer will increase the rate at which water and/or water vapor diffuses through the layer, and the pore size and thickness of the layer also will affect the passage of water, reactants and gas through the layer. The layer can be constructed of various materials, including polymeric material or coated papers. It can be constructed, e.g., from woven material, non-woven membrane, or extruded membrane, or any other material with a controlled pore distribution having a mean pore size between about 0.01 μm and about 50 μm. Suitable woven materials include any material woven from cotton, metal, polymer threads, metal threads or the like into a cloth or mesh. Extruded membranes, which include cast membranes, are preferred, and include 0.65 micron pore size, 230 to 260 micron thick, hydrophilic polyethylene membrane sold under the trade designation MPLC from Millipore (Bedford, MA), 0.65 micron pore size, extruded hydrophobic polyethylene material sold under the trade designation DOHP by Millipore (Bedford, MA). Also preferred is the cast membrane 3 micron pore Nylon 6,6 material sold under the trade designation BIODYNE A by Pall (Port Washington, NY). Non-woven membranes are membranes formed from materials such as cellulose or polymers. Other cast membranes include 0.45 pore, hydrophilic Nylon 6,6 membranes with a polypropylene backbone sold under the designation BA05 by Cuno Incorporated (Meriden, CT); 0.45 pore, hydrophilic polypropylene membrane available from 3M (City, State); and 0.45 pore size, 180 to 240 micron thick, hydrophilic Nylon 6,6 membranes sold under the designations 045ZY and 045ZN by Cuno Incorporated (Meriden, CT). Also suitable are hydrophobic, liquid water permeable non- woven polyethylenes, such as the TYVEK® 1025D polyethylene material from DuPont Company (Wilmington, DE).

Also suitable for use in constructing the apparatus of the invention are composite layers, including, but not limited to, starch/polymer composite layers. One currently preferred composite layer is a hydrophilic, 114μm thick, non-woven rice starch/polyethylene composite sold under the designation 60MDP-P by Mishima Paper Company, Limited (Japan). This layer is heat sealable, wets easily, and keeps the reactants apart until initiation.

Non- woven membranes can be formed, e.g., by suspending the membrane material, e.g., cellulose fibers, in a liquid over a porous web and then draining the liquid to form a membrane. Non-woven membranes typically have a relatively narrow and consistent pore size distribution as compared to woven materials. Consequently, the non-woven sachet generally allows entry of less initiating agent than the woven materials having the same pore size because, generally the pore size distribution is narrower. A non- woven membrane suitable for use in accordance with the present invention is the 0.65 micron pore size, hydrophobic, non-woven polypropylene material sold under the trade designation ANO6 by Millipore (Bedford, MA).

Also suitable are membranes having a pore size between about 0.01 μm and about 50 μm. More preferably, the pore size is between about 0.05 μm and about 40 μm, and most preferably, the pore size is between about 0.10 μm and 30 μm. The pore size of the layer is measured by bubble point. Bubble point is a measurement well known in the art which determines the maximum pore size from a measurement of the minimum pressure necessary to drive a bubble of gas through a wetted membrane. Pore size affects the rate at which water and ions can diffuse through the layer in both directions. A pore size preferably is chosen that allows passage of initiating agent and, at the same time, partitions the reactants to one side of the layer at a high concentration so that the reaction rate is increased and a high efficiency maintained. The artisan can readily identify suitable equivalents of any of the foregoing by exercising routine experimentation.

Preferably, the layer is constructed from a membrane having a thickness between about 10 microns and 500 microns, more preferably between about 100 microns and 400 microns, and most preferably between about 150 microns and 300 microns. hi certain preferred embodiments, the material used to construct the layer preferably has a bubble point between about 3 psi and about 100 psi, more preferably between about 5 psi and about 80 psi, and most preferably between about 10 psi and about 70 psi. The measurement of bubble point is routine and well known in the art and typically is supplied by purveyers of membranes, films, etc.

Additionally, the layer can be constructed from material that is hydrophobic and/or hydrophilic. It can also comprise a material having one or more hydrophilic zones and one or more hydrophobic zones. These zones can be created, e.g., by printing a functional chemical group or polymer onto a surface of the layer that is hydrophilic or hydrophobic or charged to create one or more hydrophilic or hydrophobic or charged zones. For example, a sulfonic acid group can be disposed on the surface of the polypropylene membrane, creating zones that are both hydrophilic and negatively charged (R-SO ^"). The membrane can then washed with a dilute acid such that the ion exchange groups (R-SO₂ ^") bind the H⁺ ions. These H^1" ions can later be released to supply H⁺ ions to acid activate reactant, e.g., chlorite, as a replacement or supplement to acid reactant.

When the layer is constructed of hydrophobic material, the hydrophobic material preferably has a flow time between about 10 sec/500ml and about 3,500 sec/500ml for 100% IPA at 14.2 psi. More preferably, the material has a flow time between about 60 sec/500ml and about 2,500 sec/500ml for 100% LPA at 14.2 psi, and most preferably, the material has a flow time between about 120 sec/500ml and about 1,500 sec/500ml for 100% J-PA at 14.2 psi.

When the layer is constructed of hydrophilic material, preferably has a flow time between about 5 sec/500 ml and about 800 sec/500 ml for 100% J-PA at 14.2 psi. More preferably, the material has a flow time between about 20 sec/500ml and about 400 sec/500ml for 100% IPA at 14.2 psi, and most preferably, the material has a flow time between about 50 sec/500ml and about 300 sec/500ml for 100% IPA at 14.2 psi. Measurement of flow time is routine and well known in the art. Yet another alternative embodiment uses a material to construct the layer that has a first surface that is hydrophilic and a second surface that is hydrophobic. For example, a layer can be constructed from such a material such that the hydrophilic surface is on the outside of the layer and the hydrophobic surface is on the inside of the layer. The exterior, hydrophilic surface aids the initiation of the reaction since water will readily wet a hydrophilic surface and pass through the layer. However, once through the layer, the hydrophobic, interior surface limits the reverse water passage through the layer. This keeps the reactants concentrated within the sachet while allowing the gas to escape thus exploiting the advantages of the discoveries disclosed herein. One such material suitable for use in the present invention is a non- woven membrane 0.65 micron pore size diameter formed from a hydrophobic material, such as polypropylene, that has been chemically functionalized with amines and carboxyl groups to produce a charged, hydrophilic surface.

Also suitable for constructing apparatus of the invention is water vapor selective material. This material can have a thickness between about 5 microns and about 400 microns thick, a pore size between about 0.05 microns and about 10 microns, and a water intrusion pressure between about 30 millibars and about 4,000 millibars. Preferably, the water vapor selective material is adhered to or otherwise supported by a support layer that allows liquid water to permeate the support layer, and the overall thickness of both the water vapor selective layer and the support layer is between about 1 mil and 20 mils. More preferred, are water vapor selective materials having a thickness between about 15 microns and about 200 microns thick, a pore size between about 0.25 microns and about 5 microns, and a water intrusion pressure between about 100 millibars and about 2,500 millibars. Preferably this layer has a water permeable support layer such that the total thickness of both layers is between about 2 mils and about 10 mils. Most preferred, are water vapor selective materials having a thickness between about 20 microns and about 100 microns thick, a pore size between about 1 micron and about 3 microns, and a water intrusion pressure between about 200 millibars and about 1000 millibars. Preferably this layer has a water permeable support layer such that the total thickness of both layers is between about 3 mils and about 8 mils. Additionally or alternatively, pore size of the water vapor selective layer can be selected to produce the desired release at specific depths of water in which the apparatus will be used. A smaller pore size will correspond to deeper operation by increasing the amount of hydraulic water pressure that the membrane will experience while remaining impermeable to liquid water.

Water vapor selective layers suitable for use in constructing the apparatus of the present invention preferably have water vapor permeability of between about 2,000 g/m²/24hrs and about 150,000 g/m²/24hrs, as determined by JIS L 1099-1985 (Method B), "Testing Methods for Water Napour Permeability of Clothes," from the Japanese Standards Association. Water vapor selective layers preferably have a resistance to liquid water permeation of at least about 30 millibars as determined by ISO 811-1981 "Textile fabrics - Determination of resistance to water penetration - Hydrostatic pressure test" published by the International Organization for Standardization. Optionally, the water vapor selective layer or layers of the present invention can include a support layer to increase the strength of the layer, and/or to increase its ability to bond to the other materials used to construct the apparatus. The support layer preferably allows diffusion or passage of initiating agent to the surface of the water vapor selective layer. For example, the support layer can be spun, perforated or have large pores that allow passage of liquid water and vapor to the surface of the water vapor selective layer. The support layer can be affixed to the water vapor selective layer by any means, for example, lamination, casting, co-extrusion, and or adhesive layers. Preferably, the sachet is constructed so that the water vapor selective layer faces the interior of the sachet. The support layer itself can be hydrophilic and/or hydrophobic. If hydrophilic, the material can be used to attract and deliver liquid water and/or vapor to the surface of the water vapor selective material. Suitable support layers include, but are not limited to, polyethylene, polypropylene, nylon, acrylic, fiberglass, and polyester in the form of woven, non- woven, and mesh layers. Preferably, the support layer thickness is between about 1 mil and 20 mils.

Suitable water vapor selective materials previously described herein include the 0.60 micron pore size, hydrophobic, polypropylene (PP) membrane having a thickness between about 250 microns and about 300 microns sold under the designation 060P1 by Cuno Incorporated (Meriden, CT). Also suitable is the 0.65 micron pore size, hydrophobic polyethylene material sold under the trade designation DOHP by Millipore (Bedford, MA)

Another water vapor selective material, suitable for use in a rapid release apparatus, includes a 1.75 mil thick, hydrophobic polytetrafluoroethylene (PTFE) layer thermally bonded to a 5 mil thick, hydrophobic polyethylene (PE) support layer sold under the trade designation BHA-TEX® by BHA Technologies (Kansas City, MO). Its resistance to liquid water permeation is at least about 500 millibar.

Also suitable are perforated films or layers constructed of layers having a water vapor transmission rate (WNTR) between about 50 g/m²/24 hrs and about 1,000 g/m²/24 hrs, more preferably, between about 200 g/m /24 hrs and about 800 g/m /24 hrs, and most preferably, between about 400 g/m²/24 hrs and about 700 g/m²/24 hrs. The measurement of water vapor transmission rate is routine and well known in the art. Also, the perforated layer preferably is hydrophobic.

Perforated films suitable for the construction of the apparatus in accordance with the present invention include, but are not limited to, polymeric material, e.g., Cryovac® perforated films available from Sealed Air Corporation (Duncan, SC). One such film is a hydrophobic polypropylene copolymer film sold under the designation SM700 by Sealed Air Corporation and has 330 holes per square inch having a diameter of 0.4 mm, a 6.4% perforated area, a thickness of about 20 microns, and a water vapor transmission rate of 700 g/m /24hrs. Another suitable film is a hydrophobic polypropylene copolymer film sold under the designation SM60 by Sealed Air Corporation and has 8 holes per square inch having a diameter of 0.4 mm, a 0.2% perforated area and a water vapor transmission rate of 65 g/m²/24hrs. The artisan can readily identify suitable equivalents of any of the foregoing by exercising routine experimentation.

In another preferred embodiment, the apparatus layer or layers can be constructed from hydrophobic, liquid water permeable material, such as polyethylene or polypropylene. These materials preferably are between about 1 mil and about 10 mils thick with a water intrusion pressure of about 30 millibars or 30 millibars or less. Hydrophobic materials suitable for use as layers in accordance with the present invention include, but are not limited to, non-woven polyethylene such as the TYNEK® non- woven polyethylenes from DuPont Company (Wilmington, DE), e.g., the TYNEK® 1025D non-woven polyethylene which has an intrusion pressure of less than 30 millibars.

The apparatus can be constracted, at least in part, from a hydrophilic membrane having a pore size between about 0.01 microns and about 50 microns. More preferably, the pore size is between about 0.05 microns and 40 microns, and most preferably, the pore size is between about 0.1 and about 30 microns. Preferred membranes also include, but are not limited to, the microporous ultra high density polyethylene membrane sold under the trade designation MPLC from Millipore (Bedford, MA), and the microporous Nylon 6,6 membrane sold under the designation 045ZY by Cuno Incorporated (Meriden, CT). Selective transmission films can also be employed. Generally, a film that has a high carbon dioxide transmission rate is preferred. While not wishing to be bound to any theory, it is thought that the carbon dioxide transmission rate approximates the chlorine dioxide transmission rate because chlorine dioxide and carbon dioxide are about the same size. Preferably, the selective transmissive film has a selective gas transmission rate of between about 500 cc/m²/24hrs and about 30,000 cc/m²/24hrs for CO₂ and between about 1,000 cc/m²/24hrs and about 10,000 cc/m²/24hrs for O₂. More preferably, the apparatus is constructed of a material having a selective gas transmission rate of between about 1,000 cc/m²/24hrs and about 25,000 cc/m²/24hrs for CO₂ and between about 2,000 cc/m²/24hrs and about 10,000 cc/m²/24hrs for O₂. Most preferably, the apparatus is constructed of a material having a selective gas transmission rate of between about 5,000 cc/m²/24hrs and about 25,000 cc/m²/24hrs for CO₂ and between about 3,000 cc/m²/24hrs and about 10,000 cc/m²/24hrs for O₂. Measurement of selective gas transmission rate is routine and well known in the art. One suitable selective transmission film is a multilayered polymer film having a carbon dioxide transmission rate of 21,000 cc/m²/24hrs and an oxygen transmission rate of 7,000 cc/m²/24hrs sold under the trade designation PD-961 Cryovac® selective transmission film from Sealed Air Corporation (Duncan, SC). In embodiments employing impermeable layers, such layers preferably have a water vapor transmission rate (WVTR) of less than about 50 g/m²/24 hrs at 70% relative humidity. More preferably, the impermeable layer has a water vapor transmission rate (WNTR) of less than about 2 g/m²/24 hrs at 70% relative humidity. Most preferably, the impermeable layer has a water vapor transmission rate (WNTR) of less than about 0.5 g/m²/24 hrs at 70% relative humidity.

Impermeable layers can be constracted of various materials, including metals, polymeric material and/or coated papers. Other suitable materials for forming impermeable layers include, but are not limited to, polymeric layers constracted from, e.g., polyethylene, polypropylene, polyester, styrene, including polystyrene, polyethylene terephthalate, polyethylene terephthalate glycol (PETG), polyvinyl chloride, polyvinylidene chloride, ethylvinyl alcohol, polyvinyl alcohol, including polyvinyl alcohol acetate, acrylobutylstyrene and/or polytetrafluoroethylene, polyacrylate and polyamide, including nylon. Also suitable are metallized layers, e.g., any of the above polymeric layers that have been metallized. Also suitable are metallic foils, such as aluminum foils. Various other impermeable materials can be used to form the barrier film as well, such as glass or ceramics. In addition layers that are composites of the above layers and/or laminates of the above layers, e.g., paper/film/foil composites are also suitable for use as a barrier layer. One preferred impermeable layer is a 5 mil thick impermeable layer comprising a polyester exterior, a metallized biaxially oriented core, and a polyethylene interior sealing layer available from Sealed Air Corporation (Duncan, SC). This layer has a water vapor transmission rate of 0.01 g/100in²/24hrs at 70% relative humidity and 122°F. Another currently preferred impermeable layer is constructed from polyvinyl chloride. Yet another preferred impermeable layer is constracted from polyethylene terephthalate glycol (PETG). Of course, it is to be understood that any of the aforementioned layers can readily be employed to construct any of the apparatus described herein, e.g._Λ sachets, envelopes, and patches.

In yet another aspect, the present invention features a kit for the delivery of a gas which includes any of the apparatus described herein. In one embodiment, the kit contains a reactant, e.g., aqueous soluble acid, aqueous soluble chlorite, and an initiating agent. This kit also includes an adhesive to secure the apparatus to the surface to be treated. The kit can come in the form of a patch, a tape, a humidifier attachment, or a sealing kit. The following illustrations of the present invention are meant to illustrate exemplary embodiments of the present invention and should not be construed as limiting.

EXEMPLIFICATION

EXAMPLE 1: REMEDIATION OF MOLD EMBEDDED IN PLASTER A 5" by 5" patch was constracted from two layers. One layer was a 1.75 mil thick, hydrophobic polytetrafluoroethylene (PTFE) layer thermally bonded to a 5 mil thick, hydrophobic polyethylene (PE) support layer sold under the trade designation BHA-TEX® by BHA Technologies (Kansas City, MO). The other was an impermeable layer comprised of a lamination of polyester, metallized biaxially oriented polypropylene layer, and linear low density polyethylene obtained from Sealed Air

Corporation (Duncan, SC). About 20 milligrams of chlorine dioxide gas in solution was applied to a gauze layer and sealed within the 5" x 5" patch (Figure 9A, impermeable side down).

The patch was applied to a portion of a plaster ceiling, as shown in Figure 9B, with adhesive applied to the perimeter. The plaster ceiling had been previously treated in another area (not shown) with surface fungicides which had been observed to kill the surface mold but not the embedded mold. The patch was adhered to the surface for eight hours. Upon removal of the patch, no visible signs of either the surface mold or the embedded mold were present were the patch had been applied to the surface (See Figure 9C). Additionally, a check at six weeks revealed no mold growing back in the treated area. EXAMPLE 2: REMEDIATION OF EMBEDDED MOLD IN PLASTER

In order to determine if a lower concentration of chlorine dioxide gas was effective in killing the embedded mold, a 5" by 5" patch was constructed as described in Example 1, except that the solution included only 5 mg of chlorine dioxide gas. The patch was adhered to an untreated portion of the plaster surface that included the embedded mold. Both the surface and embedded mold were eliminated without whitening the area which the patch was adhered to. This patch is suitable for use on materials where stronger concentrations of chlorine dioxide might bleach or otherwise damage the material.

EXAMPLE 3: REMEDIATION OF EMBEDDED MICROBIAL

CONTAMINANTS IN A ROOM

ClO₂ was delivered to an office conference room that had recently been damaged in a flood. The room showed the typical signs of mold such as mildew and odors. Several attempts to clean and rid the area of mold, including the carpet and surface areas, using conventional cleaners had been previously tried and were unsuccessful.

An apparatus similar to that shown in Figures 2A and 2B was constracted and employed to disperse the ClO₂ gas into the room. The inner sachets were constructed from two 2.5 inch x 2 inch sheets of 0.45 pore size, 180 micron thick, hydrophilic Nylon 6,6 membrane sold under the designations 045ZY by Cuno Incorporated (Meriden, CT). The third sachet was constructed from two 3.5 inch x 3.5 inch sheets of 0.60 micron pore size, hydrophobic, polypropylene (PP) membrane having a thickness between about 250 microns and about 300 microns sold under the designation 060P1 by Cuno Incorporated (Meriden, CT). The outermost envelope was constructed from two 4.5 inch x 4.5 inch sheets of a selective transmission multilayered polymer film having a carbon dioxide transmission rate of 21,000 cc/m²/24hrs and an oxygen transmission rate of 7,000 cc/m²/24hrs sold under the trade designation PD-961 Cryovac® selective transmission film from Sealed Air Corporation (Duncan, SC). A 1 inch x 3 inch frangible pouch was constracted from an E-Z Open Cryovac® laminate from Sealed Air Corporation. Three sides were first sealed, the frangible pouch filled with water, and the last side sealed with an impulse sealer. The apparatus was taken to the approximately 10' by 15' conference room and the generation of gas was initiated by manually rapturing the frangible pouch containing the water. The room was sealed off for two days. At the end of the two days, the mold and odor could not longer be detected. Even four months after treatment, no evidence of mold recurrence had been detected.

Equivalents Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.

Claims

What is claimed is:

1. A method for remediating an embedded microbiological contaminant, the method comprising: exposing an embedded microbiological contaminant to a gas, wherein the gas comprises at least one gas selected from the group consisting of chlorine dioxide, sulfur dioxide, ethylene, and ethylene oxide, thereby remediating the embedded microbiological contaminant.

2. The method of claim 1, wherein the microbiological contaminant is embedded in a porous surface.

3. The method of claim 1, wherein the microbiological contaminant is embedded in a textured surface.

4. The method of claim 1, wherein the microbiological contaminant comprises a mold, mildew, a fungus, a bacterium, or a virus.

5. The method of claim 1, comprising exposing the embedded microbiological contaminant to a chlorine dioxide gas at a concentration between about 0.1 ppm and about 100 ppm.

6. The method of claim 1, comprising the step of generating the gas from a reactant disposed in an apparatus adhered to a surface comprising the embedded microbiological contaminant.

7. The method of claim 6, wherein the apparatus comprises a pouch disposed about the reactant.

8. The method of claim 7, wherein the pouch comprises a water vapor selective layer adjacent the surface comprising the embedded microbiological contaminant.

9. The method of claim 7, wherein the pouch comprises a selective transmission film adjacent the surface comprising the embedded microbiological contaminant.

10. The method of claim 7, wherein the pouch comprises an impermeable layer disposed opposite the surface comprising the embedded microbiological contaminant.

11. The method of claim 7, wherein the pouch comprises an adhesive about its perimeter and facing the surface comprising the embedded microbiological contaminant.

12. The method of claim 7, wherein the apparatus comprises a frangible pouch containing an initiating agent disposed in the pouch.

13. The method of claim 7, comprising imtiating the reactant by dipping or sponging water onto the apparatus.

14. The method of claim 1, wherein the remediating includes killing or inactivating the microbiological contaminants.

15. The method of claim 1 , wherein the remediating includes killing or inactivating an embedded mold spore population and/or an embedded mold population.

16. The method of claim 1 , wherein the embedded microbiological contaminant is embedded in a portion of drywall, plaster, or stucco.

17. The method of claim 1, wherein the embedded microbiological contaminant is embedded in car upholstery.

18. The method of claim 1 , wherein the embedded microbiological contaminant is embedded in rag or carpet.

19. The method of claim 1, wherein the embedded microbiological contaminant is embedded in a surface in a crawl space or attic.

20. The method of claim 1, wherein the embedded microbiological contaminant is embedded in ceiling tiles.

21. The method of claim 1 , wherein the embedded microbiological contaminant is embedded in a portion of grout.

22. The method of claim 1, wherein the method comprises remediating an embedded microbiological contaminant in a bathroom, kitchen, restaurant, gym, medical facility, dental office, locker room, or aquatic facility.

23. The method of claim 22, comprising the step of sealing off a room prior to exposing the embedded microbiological contaminant to the ClO₂ gas.

24. The method of claim 1, comprising dispersing the ClO₂ gas in a gas dispersion device.

25. The method of claim 24, wherein the gas dispersion device is a fogger, a spray bottle, an atomizer, a sprayer system, a dispersion wand, a nebulizer, a sparger, or a humidifier.

26. An apparatus for remediating an embedded microbiological contaminant comprising a reactant that generates a gas, wherein the reactant is enclosed, at least in part, by a permeable layer, and the gas remediates an embedded microbiological contaminant.

27. The apparatus of claim 26, wherein the reactant is disposed in a pouch comprising the permeable layer.

28. The apparatus of claim 27, wherein the permeable layer is a water vapor selective layer or a selective transmission film.

29. The apparatus of claim 27, wherein the pouch comprises an impermeable layer disposed opposite the permeable layer.

30. The apparatus of claim 26, wherein the reactant comprises an aqueous soluble acid and an aqueous soluble chlorite.

31. The apparatus of claim 26, wherein the apparatus includes an initiating agent disposed in a frangible pouch.

32. The apparatus of claim 26, wherein the apparatus comprises an adhesive strip disposed about its perimeter.

33. The apparatus of claim 32, wherein the apparatus is in the form of a strip for application a surface comprising the embedded microbiological contaminant.

34. The apparatus of claim 26, further comprising a dispersion device for dispersing the gas.

35. The apparatus of claim 34, wherein the dispersion device is a fogger, a spray bottle, an atomizer, a sparger, or a humidifier.

36. The apparatus of any of claims 26-35, wherein the gas comprises at least one gas selected from the group consisting of chlorine dioxide, sulfur dioxide, ethylene and ethylene oxide.

37. A kit comprising the apparatus of any of claims 26-36.