MATERIALS

FIELD OF THE INVENTION

The present invention relates, generally, to a method for remediation of hazardous materials and particularly to a method of remediation of highly hazardous waste including asbestos fibers by encapsulation.

BACKGROUND OF THE INVENTION

Asbestos is the common name for six different naturally occurring fibrous silicate minerals. Asbestos has been prized since ancient times because the fibers are extremely resistant to heat, flame, electrical and chemical damage, they absorb sound, are odorless and tasteless, very flexible, lightweight, and have a high tensile strength. Some of these same properties, however, have been found to make the substance deadly when its fibers get lodged within the human lung. Inhalation of asbestos fibers is linked to mesothelioma as well as lung cancer and asbestosis, which is a severe scarring of the lungs. Worldwide, more than 100,000 people die each year from occupational exposure to Asbestos, and hundreds more die each year from non-occupational exposures, according to the World Health Organization (WHO). Much of this number could come more from activity in the UK and Spain where people are exposed to the more hazardous blue and brown asbestos fibers. The most prevalent asbestos materials are:

Serpentine Mineral; CAS 12001-29-5, Mg3Si205(OH)4. Characterized by curly fibers. The only Serpentine member is believed to be Chrysotile white asbestos; which constitutes 95% of this class which is found predominantly in North America. This mineral form is said to be less hazardous than the Amphibole mineral asbestos type fibers next discussed. Amphibole Mineral. Characterized by needle-like straight fibers; Two fibers are this type:

• Amosite; CAS 12172-73-5, Fe ₇ Si ₈ 0 ₂₂ (OH)2. Characterized by brown fibers.

Mined predominantly in South Africa,

· Crocidolite; CAS 12001-28-4 Na ₂ (Fe ⁺² 3Fe ⁺³ ₂ ) Si ₈ 0 ₂₂ (OH) ₂ . Considered to be the most toxic of the six minerals and often referred to as blue asbestos. Characterized by soft needle-like straight fibers,

Other Minerals:

• Anthophyllite; CAS No. 77536-67-5, (Mg, Fe)7Si8022(OH)2. Characterized by grey-brown color fiber.

• Tremolite, CAS 77536-68-6 Ca2Mg5.0-4.5Si8O22(OH)2. Characterized by white, green, grey or transparent fiber. These fibers are lesser known.

• Ackinolite CAS 77536-67-5 Ca2(Mg5.0-4.Fe+20.5-2.5)Si8O22(OH)2.

Lesser known.

Asbestos fibers can be woven into cloth or spun into yarn. They can also be added to cement, plastics and other substances.

Many people know asbestos can be harmful to the human body and that the U.S. and other governments starting with Iceland banned the use of asbestos outright. However, in the US and Canada, the concept of a total ban is simply not true. Products containing asbestos are still manufactured and sold in the United States today, and there are hundreds of thousands of buildings still standing that have asbestos-containing materials within them. In 1989, the U.S. Environmental Protection Agency (EPA) enacted the "Asbestos Ban and Phase out Rule," applying to manufacture, import, processing and distribution of all asbestos products, affecting 94 percent of all asbestos consumption. The ban and phase out were overturned by the U.S. Fifth Circuit Court of Appeals in 1991. Today, the asbestos ban covers only a few items under the Toxic Substances Control Act (TSCA) and the Clean Air Act such as corrugated, specially and commercial papers, flooring felt, and certain spray-on materials and any new applications.

The U.S. EPA has defined Asbestos-Containing Material (ACM) as a material which contains greater than one percent (1%) asbestos and requires special handling of such material. In accordance with various regulatory procedures, various safeguards are employed to protect workers from inhaling asbestos fibers during removal or demolition activities. Such safeguards include requiring workers to wear approved respiratory apparatus as well as protective clothing requiring in any area of a building where ACM is being removed. The enclosed work area must be kept at a negative pressure by the use of special apparatus equipped with HEPA filters to prevent airborne asbestos fibers from leaving the work area. Such isolation of the work area is an expensive and time- consuming part of the process.

Most asbestos abatement professionals agree that unless the asbestos material is considered "friable," easily broken, or damaged, it is safer to leave it in place than to remove it. Almost all buildings constructed prior to 1980 contain asbestos in one or more applications. However, when asbestos does become friable, it takes very little pressure to dislodge its microscopic fibers, which then become airborne and can be inhaled, leading to cancer and other diseases. Thus, a reliable method to microencapsulate these fibers could provide a significant advantage to those who could otherwise be exposed.

The carcinogenic toxicity of asbestos has been known for centuries and may lead to one or more diseases for those who have inhaled it. The most common asbestos- related condition is pleural plaques, which are small areas of fibrous collagen tissue that usually occur on the parietal pleura. They are not pre-cancerous, but they do indicate asbestos exposure and as such are a harbinger of other diseases like asbestosis or mesothelioma which is most serious. Mesothelium surrounds the lungs (pleura), although it can also strike in the abdominal cavity (peritoneal mesothelioma).

Asbestos is present in building walls, ceilings, pipes, ducts, boilers, tanks, etc., and insulation surrounding the same, as well as new products and other ACM's. Asbestos constitutes a serious threat to the health of the users of such buildings, which include hospitals, schools, and other public and private accommodations. Airborne asbestos fibers can enter the body and cause asbestosis, lung cancer, mesothelioma, and other cancers. The asbestos can be sprayed onto a surface, troweled onto a surface, or constitute an integral part of the material which is formed into the structure such as ceiling tiles, floor tiles, wall boards, etc. Asbestos that can be crumbled or pulverized with simple hand pressure is considered friable having the greatest potential of becoming air borne and creating the health dangers previously mentioned.

Asbestos Fiber Alteration Prior to Use

Generally, prior art methods for handling asbestos containing building materials have taken several approaches. One approach has been to chemically alter asbestos fibers before using them in building products. This approach is discussed in U.S. 4,328,197 and 4,401 ,636, both to Flowers and in U.S. Pat. No. 4,474,742 to Gracelfa et al.

Grecelfa et. al. (U.S. Pat. No. 4.474.742) teaches treatment of asbestos with hydroxamic acid and iron chelating agents to remove the iron present in the asbestos based on the presumption that the iron is the harmful component. In the Flowers patents (U.S. Pat No. 4,328,197 and U.S. Pat. No.4,401,636), one is taught to contact asbestos fibers with an aqueous solution of a Weak Base Strong Acid or a Strong Base/Weak Acid salt of manganese, chromium, cobalt, iron, copper, or aluminum or mixtures thereof, to convert the asbestos fibers into a metal-micelle product. In general, the process contemplated by Flowers is affected by preparing an asbestos fiber slurry in an aqueous solution of the appropriate salt, effecting the conversion of the asbestos fibers to metal-micelle fibers recovering the metal-micelle fibers from the slurry for use in the subsequent preparation of the desired fiber-containing end product.

In U.S. 4,309,477 to Pezzoli, the asbestos is sprayed with an ionizable salt solution or the asbestos is slurried in the ionizable salt solution for a sufficient time to allow the surface of the asbestos to be contacted. The salt solution contains at least one metal sulfide. Thus, Flowers and Pezzoli do not address the problem of dealing with asbestos already contained in existing building structures, but rather products made with treated asbestos. Moreover, treatments like these are designed to reduce the level of irritation that the treated asbestos fibers pose to living cells relative to that posed by the untreated asbestos fibers. Such treatments do not necessarily prevent the formation of airborne asbestos fibers.

Asbestos Fiber Alteration After Use

Dry Asbestos Removal

A number of removal techniques are available, each with advantages and disadvantages. For example, if one may simply scrape or chip away at dry untreated asbestos-containing material and collects the scrapings for discard. This technique, referred to as dry removal, is generally considered unacceptable by regulatory authorities since it provides no safeguard against the release of airborne asbestos particles. Dry vacuum methods have been used to overcome the problems of dry removal by incorporating an exhaust filtering system to prevent pollution outside environment and using sealed containers for storing and discarding the collected asbestos-containing material. The disadvantage of the dry vacuum method is that the bond between the dry building material and the underlying surface on which it is coated may be stronger than the vacuum capabilities of the equipment. In those cases, it is necessary to dislodge at least a portion of the asbestos containing material by scraping or chipping, which has the same limitations as the dry removal process described above.

Wet Asbestos Removal

Wet removal processes were developed to reduce the problems associated with dry removal techniques. Wet removal generally involves wetting a building material with water or water-surfactant solution to soften it and facilitate its removal. Wet removal clearly represents an improvement over dry removal. However, the use of water as a softening agent is not entirely satisfactory because water penetrates slowly, does not completely wet most building materials, and tends to run off the surfaces being treated.

Over the years, wet removal techniques were improved by devising more effective wetting and/or softening compositions. A number of surface treatment methods have been proposed and evaluated for the purpose of modifying certain predetermined properties of the asbestos fibers. These procedures include: coating the surface of asbestos fibers with a phosphate, polyphosphate, or corresponding acid to improve the filtration characteristic of the fibers (US 3,535,150 to Lipsett; US 3,957,571 to Bodycomb Jr.). Asbestos was treated with magnesium carbonate or an oxide of a polyvalent metal to enhance the tensile strength (US 1,982,542 to Seigel; US 2,451,805 and US 2,460,734 to Callinan) of the asbestos fabric coating with an insoluble inorganic oxide to render the fabric flame resistant and water repellent (US. Pat. No. 2,406,779 to Kurlychek) mixing an organic surface-active agent with fibrous asbestos agglomerates to disperse the asbestos fibers. (US. 2,626,213 to Novak) distributed small amounts of polymeric particles. A water-soluble macromolecular organic substance was dispersed throughout an asbestos product to reduce dust emitted by the asbestos during handling and use (US 3,660,148 to Heron; 3,967,043 to Otouma and Nakamura).

Over the past several years, wet removal techniques were improved by devising more effective wetting and/or softening compositions. Recent U.S. patents which relate to such improved wet removal techniques include, for example. U.S. Pat. No. 4,347,150 to Arpin; U.S. Pat. No. 4,693,755 to Erziner; and U.S. Pat. No. 5,258,562 to Mirick et al.

The Arpin patent discloses a technique for wetting and removing friable insulating materials from an underlying substrate using a two-part wetting system. The first component of the system comprises an aqueous alkali metal silicate dispersion blended with a cationic or nonionic surfactant and the second component comprises a mixture of an acrylic latex and a reagent that is reactive with the alkali metal silicates in the first part. The two parts are stored separately and are mixed shortly before use to form a stripping composition which facilitates the removal of the building material. The removed material must be handled as an asbestos-containing material.

The Ezinger patent exemplifies a wet method for removing asbestos-containing materials from a substrate. This patent discloses applying a composition containing a cellulosic polymer to the asbestos-containing material, allowing the cellulosic polymer- containing composition time to penetrate and wet the asbestos-containing material. Removing the wet material from the underlying substrate by mechanical forces, and collecting the removed material for discard. The Mirick et al patent is centered on the concept of removing asbestos fiber containing building material by applying a dilute aqueous solution of an acid, which may include a separate source of fluoride ions such as an alkali metal or ammonium salt of hydrofluoric acid to the building material for the purpose of conditioning the material to aid in its removal while partially converting the asbestos fibers.

A composition in US 5,753,031 to Block for transforming a Chrysotile asbestos containing material into a non-asbestos material is disclosed, wherein the composition comprises water, at least about 30% by weight of an inorganic acid, and from about 0.1 to about 4% by weight of a hexafluorosilicate of ammonia, an alkali metal or an alkaline earth metal. A method of transforming the asbestos-containing material into a non- asbestos material using the present composition also is disclosed.

The building material, after having been treated with the dilute acid solution, is preferably removed for further treatment and/or discard. Mirick et al further contemplates that the wet building material, once removed, can then be digested by immersing the material into a bath of an acid solution, with heating and agitation until all of the asbestos material has been destroyed.

Several problems are associated with wet removal techniques. The treatment solutions are conventionally applied to the building material by spray or brush application. These application techniques have an abrasive quality which may dislodge at least a portion of the surface of the building material causing some asbestos fibers to become airborne. Further, such application can provide delivery of only small amounts of the active materials on a per pass basis. Attempts to apply greater amounts on a per pass application merely causes run-off of the excess over that which the building material is capable of absorbing within the application time. Thus, even attempts to totally wet a material is difficult to achieve, and requires at least, multiple applications of limited amounts. Finally, the conventional means of applying liquid to asbestos- containing materials do not provide a way to control dosage. It is desired to have a means of applying a composition capable of transforming Chrysotile asbestos containing material to a non-regulated material in an effective and efficient manner.

Asbestos Treatment to Leave In-Place by Encapsulation

The word "encapsulate" may have many meanings, depending on the dictionary "type" used and the substrates involved. In science, the definition of the word encapsulate is to "encase an entity in or as if in a capsule or use a certain sized capsule capable of putting boundaries around the entity." This definition of encapsulate is adopted herein and shall be used for the purpose of the present disclosure.

The encapsulation method of most of the earlier patent literature involves placing wall boards around the asbestos material with a sealant, close the cracks and holes areas or spray the sealant on the wallboard to bond the fibers to the wallboard so as to prevent them from delaminating from the structure, and becoming airborne outside the entity. However, encapsulation by this means was not always effective in preventing the asbestos fibers from delaminating from the substrate and becoming airborne outside the unit. Containment walls were expensive to build and also resulted in a loss of building space. U.S. 1,850,787 to Brisinger involves covering wall boards formed of a fibrous composition. The wall boards are completely covered with sheets of fabric, and a thin coat of plastic material is applied to the fabric to provide a finishing surface. The finishing coat is made of an elastic and tough, but not brittle material, and a bond is actually formed between the finishing coat and the fabric so that cracks are eliminated regardless of the ordinary distortion of the walls caused by settling of the building, vibration, or other causes. These sheets are adhesively secured to the asbestos wall boards and are firmly secured thereto by a suitable adhesive in the manner substantially the same as wall paper is applied to a wall. The edges of the fabric are preferably laid in abutting relation. The sheets of fabric are preferably a tough cloth fabric such as tough muslin. An example of a suitable plastic material includes a mixture of flat paint with substantially equal parts of plaster of paris and whiting.

Another approach is to treat previously formed asbestos containing building materials by encapsulating the materials to thereby prevent the asbestos fibers from becoming air borne. A resinous encapsulating coating material typically would be applied by spraying, brushing or trowelling. Care must be taken when using encapsulating methods so as not to physically damage the building material being encapsulated. Encapsulation is a containment method and, the encapsulated asbestos material remains in place during the life of the building.

U.S. Pat. No. 3,185,297 to Rutledge discloses a fabric impregnated with uncrystallized gypsum that is formulated with an adhesive, the adhesive causes the gypsum to crystallize and form a secure bond to the substrate. Later, Rutledge disclosed in US 5,039,365 that a water soluble polyvinyl acetate emulsion coating when applied to the exterior surface of the structure provided encapsulation.

In US 8,721,818 to LaVelle describes a similar product/method to quickly and effectively prevent molds, lead, asbestos and other toxic substances from becoming airborne is presented. The method of encapsulation is essentially a toxin sealed on and in a sealed plastic bag with an adhesive substance, the sides of the bag sealed to the inside of a larger box with the adhesive and a box sealed together with adhesive and sealed around and to the bag with adhesive such that there are no openings to the toxin. SUMMARY

The present disclosure includes modifications of the, Burns et.al. US 8,115,046 B, microencapsulation technology, incorporated fully herein by reference, using different in-situ methods for applying the technology to specific classes of highly hazardous wastes. For example, for asbestos-containing materials, the technology relates to a particular method for reducing the functionality of the asbestos containing fibers and containing the asbestos fibers in existing building structures and products in a microencapsulated polymer matrix on a nano-scale such that the fibers cannot migrate or spread to be inhaled by people. For PCB's, PAHs, and perhaps drilling mud, the modifications relate to changing the silicate surfactant mixture to a highly non-ionic surfactant system. For other modifications the use of a cationic or zwitterionic surfactant is contemplated. These applications were not contemplated under the patent application, Burns et.al. US 8,115,046 B.

Using the previous definition of "encapsulate" or "encapsulation", if the prefix "micro" is used in front of the word "encapsulate" as in "microencapsulate" then the meaning of encapsulate is further defined as small "nano" size is contained within and conveyed by the definition and meaning of "micro". As used in the present disclosure, the term "microencapsulate shall mean to encase an entity such as hazardous material or fiber in or as if in a small to very small "elastic" capsule (or use a small to very small, including nano, sized capsule) capable of putting boundaries around the hazardous material or fiber.

The question becomes, how can we create a microencapsulation system that will provide satisfactory results of contacting asbestos fibers or silvers in a microencapsulation pattern without having brittleness? It is known that some Ethylene Vinyl Acetate (EVA) copolymers based on a low proportion of Vinyl Acetate (VA) (approximately up to 4%) may be referred to as a vinyl acetate modified polyethylene when plasticized with the base polyethylene polymer. When it is a copolymer and is processed as a thermoplastics material - just like low density polyethylene. It has some of the properties of a low density polyethylene but increased gloss (useful for film), softness and flexibility from the EVA. The EVA copolymer which is based on a high proportion of VA (greater than 40%) is referred to as ethylene-vinyl acetate rubber. EVA is an elastomeric polymer that produces materials which are "rubber-like" in elasticity softness and flexibility. The material has good clarity and gloss, low-temperature toughness, stress-crack resistance, hot-melt adhesive waterproof properties, and resistance to UV radiation. EVA has a distinctive vinegar-like odor and is competitive with rubber and vinyl products in many electrical applications.

This disclosure employs a thermoplastic elastomer polymer of a hydrogenated Styrene Isoprene/Butadiene Block Copolymer and plasticized it with a low molecular weight polybutene to provide properties of the polybutene which created a microencapsulation system providing satisfactory results for creating a microencapsulation medium contacting the asbestos fibers in a rubber-like manner. This material was added to Step 1 and after a short time contacted with Step 2 to create the microencapsulation matrix around the rubber like polymer coating containing the asbestos fibers.

The microencapsulation formulations (Step 1 and Step 2) relative to this disclosure are based upon a revolutionary commercial treatment process for fuels, lubricants, low polarity chemicals and other hazardous materials based on advanced surfactant technology. In the present disclosure, however, the step 1 and step 2 formulations microencapsulate a coacervated polymer system of the hazardous asbestos fibers derived from a plasticized rubber latex emulsion containing the silicate component. This coacervation creates a special type of microencapsulation process. Coacervation is the phenomenon of forming a liquid rich polymer phase such as the low molecular weight plasticized butane polymer - Styrene/Isoprene/Butadiene/Styrene Block Copolymer that is in equilibrium with the emulsified polysilicic acid from the sodium silicate component of Step 1 which is in the process of forming a polymeric "Sol" with a short time delay. This first gelatin forms a dispersion when Step 2 is added to the polymeric silicate mixture to cause coacervation as the mixture begins to harden. Further hardening will occur as the water evaporates and the polymer mix hardens.

The Step 1 and Step 2 additives consist of two water-based, non-toxic, non- hazardous solutions. The Step 1 additive is first added to the contaminant. The Step 1 additive is an aqueous, alkaline, silica reagent. The Step 2 additive is a slightly acidic, aqueous, polymeric material that rapidly reacts with the alkaline silica additive to complete the microencapsulation process. The microencapsulation process of the present disclosure encloses contaminants on a molecular level in an inert amorphous silicate matrix.

The present invention is a method for treating asbestos comprising depositing on the asbestos fiber, a material consisting essentially of an emulsified latex polymer in Step 1, prior to microencapsulation with the addition of Step 2. The microencapsulation method involves spraying the asbestos material with the Step 1 silicate and rubber latex sealant to bond the fibers together so as to prevent them from delaminating from the structure and becoming airborne. The present invention is a method for treating asbestos and other toxic entities comprising depositing on the asbestos fiber a material consisting essentially of an emulsified latex polymer, prior to microencapsulation. The microencapsulation method involves spraying the asbestos material with a sealant to bond the fibers together preventing them from delaminating from the structure and becoming airborne. Wet removal processes were developed as a means of reducing the problems associated with the various dry removal techniques. Wet removal generally involves wetting a building material with water or water-surfactant solution to soften it and to thereby facilitate its removal. It is contemplated that use of a microencapsulation technique such as described in this disclosure could solve some of these problems.

It is an object of the present invention to provide an improved composition and method for treating porous inorganic building materials which contain asbestos fibers to microencapsulate the building materials while the building materials are part of the building environment and supported on an underlying substrate prior to possible wet removal.

Another object of the present invention is to treat a building material which contains gypsum, asbestos such as Chrysotile asbestos and, optionally, other components, such as porous aggregate particulate as, for example, vermiculite, while part of a building structure, to transform the building material into a non-regulated material, with a silicate microencapsulation treatment composition that contains a polymer stable foaming agent system in an amount sufficient to provide a stable foamed treating composition that is capable of adhering to and soaking into the building material being treated. The system thereby provides a mode of applying a different method of microencapsulation prior to the silicate microencapsulation.

In accordance with the invention, these and other objects and advantages are achieved by the present compositions and method for transforming Chrysotile asbestos material and others to microencapsulated asbestos materials. The compositions comprise a unique combination of water, a chemical entity or low molecular weight polymer that will plasticize the TPE block co-polymer, and a high concentration of a non-ionic surfactant for the polymer component. This mixture is combined with the Step 1 components of the silicate microencapsulation system which contains additional water, two low concentrations of anionic surfactants and sodium silicate. This composition is first sprayed on the asbestos composition followed by a resonance time before spraying the microencapsulation setting agent (step 2, solution 2) which causes coacervation and the sodium silicate to set. This second solution setting composition is applied to the asbestos-containing materials after the plasticized polymer -silicic acid polymer composition has coated the Chrysotile fibers or other type asbestos such as Amosite (without limitation) containing building materials, in the form of a stable foam.

The present invention is intended for the treatment of porous inorganic cementitious materials which contain asbestos fibers of Chrysotile or Amosite types to transform the building materials to microencapsulated materials. The present invention is especially useful for decontaminating Chrysotile asbestos fibers contained in gypsum- based building materials that have been previously applied to the structural components such as steel beams, decking and the like of buildings as coatings thereon to provide fire and heat resistance thereto.

The present invention provides a treating composition which is an aqueous solution or dispersion in the form of a stable foam solution as Step 1. The subject plasticized polymeric and surfactant compositions constitute a unique foaming agent system comprising both anionic and non-ionic functionality in an amount capable of maintaining the treating composition in the form of a polymer stable microencapsulating foam as fully described herein.

The present disclosure includes a two-part formulation derived from water based solutions having the ability to micro encapsulate low polarity hazardous hydrocarbons, organic chemicals, asbestos fiber, inorganic chemical metals. The first solution includes water; a predetermined ratio of a water soluble alkaline silicate solution having at least one alkali metal and a predetermined ratio of at least one water soluble anionic surfactant; a predetermined ratio of at least one water soluble anionic surfactant; a predetermined ratio of at least one water soluble non-ionic surfactant; a predetermined ratio of at least one medium molecular weight polystyrene triblock copolymer fluff; and, a predetermined ratio of at least one low molecular weight liquid polybutene plasticizing entity. The alkali metal may be sodium and/or potassium. The second solution includes water and a predetermined ratio of water soluble acid; a predetermined ratio of water dispersible polymer; a predetermined ratio of a water soluble hydrotrope; a predetermined ratio of at least one water soluble flocculating agent. The second solution may further include a predetermined ratio of at least one water soluble quaternary surfactant agent and/or a predetermined ratio of a water soluble activating agent.

The first foaming solution preferably includes a molar ratio of water soluble anionic surfactant to water soluble non-ionic surfactant in the range of approximately 50:1 to approximately 10: Land most preferably approximately 50: 1 to approximately 5: 1.

The pH of the first foaming solution is less than 12, and/or approximately 12. The pH of the first foaming solution is most preferably between approximately 10 and 12. The two solution formulation of claim 1 wherein the first foaming solution is formulated to provide high cohesive and adhesive properties so as to be able to hold itself together as a mass with semi-solid rheological properties.

The foam density of the first foaming solution is preferably between approximately 0.05 g/cc to approximately 0.4 g/cc and most preferably between approximately 0.05 g/cc to approximately 0.15 g/cc.

The second solution may further include at least one water soluble flocculation agent selected from the group consisting of aluminum chlorohydrate, calcium chloride, or other metal salts, acids, and acid hydrolyzable substances. The at least one water soluble flocculation agent may be present in a concentration between approximately 5 and 65 percent by weight.

The present disclosure also includes a method of using a two-part formulation derived from water based solutions having the ability to micro encapsulate hazardous materials including low polarity hydrocarbons, organic chemicals, asbestos fiber; and inorganic chemical metals. The method includes preparing a first foaming solution including water; a predetermined ratio of a water soluble alkaline silicate solution; a predetermined ratio of at least one water soluble anionic surfactant; a predetermined ratio of at least one water soluble non-ionic surfactant; a predetermined ratio of at least one medium molecular weight polystyrene triblock copolymer; a predetermined ratio of at least one low molecular weight liquid polybutene; and, a plasticizing entity. A second solution is prepared which includes water; a predetermined ratio of water soluble acid; a predetermined ratio of water dispersible polymer; a predetermined ratio of water soluble hydrotrope; and, a predetermined ratio of at least one water soluble flocculating agent. The method further preferably includes applying the first foaming solution to a surface containing low polarity hazardous material selected from the group consisting of hydrocarbons, organic chemicals, asbestos fiber; and inorganic chemical metals; allowing the first foaming solution to contact the hazardous material for a time sufficient for the first foaming solution to penetrate the hazardous material; applying the second solution to the surface; and, allowing the second solution to contact the first solution and hazardous material to form a homogeneous mixture. The resultant homogeneous mixture may be left in place, the hazardous material being encapsulated (microencapsulated) or it may be removed. The homogeneous mixture may be removed using a wet removal process.

The first foaming solution is preferably applied to the asbestos material in a thickness of approximately 0.5 inches to approximately 2 inches.

The foregoing has outlined in broad terms the more important features of the invention disclosed herein so that the detailed description that follows may be more clearly understood, and so that the contribution of the instant inventors to the art may be better appreciated. The instant invention is not limited in its application to the details of the construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. Rather the invention is capable of other embodiments and of being practiced and carried out in various other ways not specifically enumerated herein. Additionally, the disclosure that follows is intended to apply to all alternatives, modifications and equivalents as may be included within the spirit and the scope of the invention as defined by the appended claims. Further, it should be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting, unless the specification specifically so limits the invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1A is a diagram representing microencapsulation of an organic micellular material.

Figure IB is a diagram representing microencapsulation of an asbestos fiber using the composition and method of the present disclosure.

Figure 2 is a scanning electron microscope (SEM) photograph of a control sample of a microencapsulation system at 2,000 x magnification.

Figure 3 is a SEM micrograph of crude oil encapsulated in a silicateon matrix. Figure 4 is a representation of the structure of a linear styrene block copolymer (SBC).

Figure 5 is a representation of the chemical structure of a polychlorinated biphenyl (PCB).

Figure 6 includes representations of chemical structures of representative Poly Aromatic Hydrocarbons (PAH's)

Figure 7 depicts the graphical relationship between concentrations of Cd+2 and reduction concentrations of encapsulating composition of the present disclosure.

Figure 8 depicts the graphical relationship between concentrations of Cr+6 and reduction concentrations of encapsulating composition of the present disclosure.

Figure 9 depicts the graphical relationship between concentrations of Pb+2 and reduction concentrations of encapsulating composition of the present disclosure.

Figure 10 is a graphical relationship of additive concentrations varied with respect to each known volume of contaminant concentrations plotted against the encapsulation concentration of the present disclosure. Figure 11 depicts a table of extraction of known volumes of hazardous materials in various types of soil using EPA test parameters.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Using the previously enumerated definition of encapsulation, one can visually see the described capsule that contained the entity. Encapsulation by itself sometimes suggests that it is not always an effective method to prevent the asbestos fibers of delaminating from the substrate and becoming airborne. If the prefix "micro" is used in front of the word "encapsulate" as in "microencapsulate" then the meaning is much different as size actually becomes defined in the word meaning of "micro". The present invention is a method for treating asbestos comprising depositing on the asbestos fiber, a material consisting essentially of an emulsified latex polymer, prior to micro encapsulation. The microencapsulation method involves spraying the asbestos material with a sealant to bond the fibers together so as to prevent them from delaminating from the structure and becoming airborne. The present invention of this patent application is a method for treating asbestos and other toxic entities comprising depositing on the asbestos fiber, a material consisting essentially of an emulsified latex polymer, prior to microencapsulation. The microencapsulation method involves spraying the asbestos material with a sealant to bond the fibers together preventing them from delaminating from the structure and becoming airborne. Wet removal processes were developed as a means of reducing the problems associated with the various dry removal techniques. Wet removal generally involves wetting a building material with water or water-surfactant solution to soften it and to thereby facilitate its removal. Perhaps use of a microencapsulation technique such as this invention could solve some of these problems. A stated above, the microencapsulation formulations (Step 1 and Step 2) relative to this disclosure are derived from a revolutionary commercial treatment process for fuels, lubricants, and other hazardous materials based on advanced surfactant technology demonstrating microencapsulation of hydrocarbon spills at the molecular level into an inert amorphous silica-polymer matrix. This microencapsulation process originally demonstrated a process for removal of the dangerous characteristics of this waste type, such as ignitability, corrosivity, reactivity and toxicity.

The Step 1 and Step 2 additives consist of two water-based, non-toxic, non- hazardous solutions. The Step 1 additive is an aqueous, alkaline, silica reagent containing a complex formulation of biodegradable surfactants that desorb and emulsify hydrocarbons and chemicals into microscopic micelles. The surfactants orient themselves with the hydrophobic portion toward the hydrocarbon (contaminant or hazardous material) and the hydrophilic portion oriented outwards (toward the hydrophilic silica sites that form the precursor for the encapsulate shell). This product may be used with a large variety of contaminants ranging from heavy oils and sludges to light fuels and solvents. Specific surfactant packages can be designed for specific treatments to permit microencapsulation of more hydrophilic substances.

Applied second, the Step 2 additive is a slightly acidic, aqueous, polymeric material that rapidly reacts with the alkaline silica additive to complete the microencapsulation process. At room temperature, within 10 seconds, microencapsulation is observed to occur in the form of precipitated agglomerates of the silicate containing the contaminant species inside the silicate matrix. As time approaches one minute, the precipitated agglomerates firm up into a wet clay-like texture. It is believed the basic microencapsulation process encloses contaminants on a molecular level in an inert amorphous silicate matrix as illustrated in Figure 1. The pH of the microencapsulated material at this point is in the neutral range.

Figure 1A depicts a microencapsulated micelle entrapped organic material 10. As depicted, hazardous low polarity hydrocarbon, organic chemical or inorganic chemical metals, collectively 12 are entrapped in micellar molecules, collectively 14. These micelles are microencapsulated in a silica matrix 16.

Figure IB depicts a microencapsulated micelle entrapped fiber 20. As depicted fiber 22, such as an asbestos fiber. As depicted, asbestos fiber 22 is entrapped in micellar molecules, collectively 24. These micelles are microencapsulated in a silicon matrix 26.

As the silica gel dries, the silica microcapsules dehydrate, irreversibly shrinking increasing the packing density and the pore diameters diminish firmly holding the contaminants in place. Characterization results of the typical microencapsulation process suggest the resulting silicate matrix has very low permeability and leachability. The residual contaminants or highly hazardous chemicals are simply not extractable under these conditions and the matrix has impressive long-term stability.

Morphological Characterization. Fluorescence, optical microscopy photographs, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA), X-ray diffraction and mass spectroscopy research were used to characterize the morphology of the microencapsulation silicate cell matrix. Twenty volume percent of a neat crude oil sample, known to fluoresce under ultra violet (UV) light, was microencapsulated and allowed to air dry. The sample was examined using several analytical procedures. The presence of crude oil in the microencapsulated sample was observed under plane polarized light due to an oil stain on the silicate cells. The same sample was then examined under UV light. The sample did not fluoresce as expected, which was attributed to the crude oil in the microencapsulated sample. The oil stain was absent in the control sample without crude oil. SEM, coupled with EDXA, indicated that the silicate morphology has many cavernous chambers and pockets at 2,000-fold magnification, as shown in Figure 2. Figure 2 demonstrates that encapsulation exists at a very small scale.

X-ray diffraction indicated that silicate cells are largely amorphous silicon dioxide. Amorphous structures are random in nature and they are known to be very stable as opposed to a highly ordered crystalline structure. The crude oil is said to be microencapsulated, meaning it is molecularly bound by physical forces in the micelles and trapped in the fine pores of the silicate matrix. The electron micrograph RS 970546 shown in Figure 3 indicates the fine structure at the edge reflected by dark and light contrasting of the order of 50 to 100 nanometers (nm). The technology's ability to microencapsulate a high volume of oil (10 to 30 percent) on a gram of encapsulated material per gram of silicate basis is linked to the very small nanometer pore size of the microcapsule, as indicated by the fine structure on the micrograph shown in Figure 3. This microencapsulation is a nanotechnology technology since the pore size is within the generally accepted range for nanomaterials from 1 to 100 nm.

Peracetic acid (CH3COOOH) is a very strong oxidizing agent with a stronger oxidation potential than chlorine or chlorine dioxide as shown in Table 1. In the present disclosure, a strong oxidizing agent could be added to the Step 1 (first foaming solution) composition. Peracetic acid is a clear, colorless liquid with no foaming capabilities, and has a strong pungent acetic acid (vinegar) odor. Peracetic acid is a mixture of acetic acid and hydrogen peroxide in an aqueous solution (Equation 1). It is a very strong oxidizing agent and has stronger oxidation potential than chlorine or chlorine dioxide. The present invention relates to an improved method for controlling airborne asbestos fibers from existing building structures and more particularly to a method for microencapsulating and containing the threat of airborne asbestos fibers in existing building structures such as walls, ceilings, pipes, conduits, ducts, insulating surface layers, and the like, comprising asbestos fibers as an integral part thereof. The present disclosure also relates to a method of providing new products whereby the contained asbestos has been treated in this manner to detoxify the asbestos fibers. This decontamination capacity may come about by a microencapsulation technology just explained or it may be accomplished by utilizing a new decontamination process combining a polymeric process that has the capacity to be combined with the microencapsulation process.

o o

II II

CH ₃ C— OH + ¾0 ₂ »- C¾C— O— OH + ¾0.

Equation 1.

Certain types of new polymers have been discovered that were originally said to "absorb" crude oils and other hydrocarbons without much of any expansion as the hydrocarbons were "absorbed." The real situation is that this new class of hydrocarbons are really not "absorbing" the hydrocarbons. These polymers are referred to Thermoplastic Elastomers (TPEs). They are Styrene Block Copolymers with styrene end blocks and have mid-blocks of containing rubber block copolymer segments. Each segment contributes to the properties of the polymer. Figure 4 shows the typical structure of a linear SBC. Styrene end-blocks are hard copolymers adding a glassy strength to the SBC through π-π-electron stacking. This energy is similar to that provided to polymer systems a couple of decades ago by crosslinking a polymer system. The mid-blocks are composed of rubbery polymers of olefins such as isoprene, butadiene, ethylene-butene or other such copolymers which have the capacity for "stretchiness."

Examples of the SBC products that could be used in this application are:

(i) Styrene-butadiene (SB) di- block copolymers

(ii) Styrene-butadiene-styrene (SBS) tri block copolymers

(iii) Styrene-isoprene-styrene (SIS) tri block copolymers

(iv) Styrene-ethylene-butene-styrene (SEBS) block copolymers

(v) Styrene-ethylene-propylene-styrene (SEPS) tri block copolymers

(vi) Styrene-ethylene-ethylene/propylene-styrene (SEE/PS) tri block copolymers.

Certain chemicals or polymers will combine with the SBC block copolymers to plasticize the SBC polymers. A plasticizer is a substance incorporated into a plastic or an elastomer to increase its flexibility, workability or distensibility. Distensibility is the capability of being distended or stretched under pressure. Thus, a plasticizer could be a lower molecular weight organic polymer which, when added to a rigid substance, imparts the flexibility. Plasticizers include a large variety of organic liquids. Elastomer and plastic polymers may be tough, dry, or rigid materials which, for many applications, have a need for plasticizers. Among other aspects, a plasticizer can reduce the polymer melt viscosity, lower the temperature of a second order glass transition, or lower the elastic modulus of the polymer.

The present disclosure relates to an improved composition and method for treating porous inorganic building materials which contain asbestos fibers to miroencapsulate the building materials while the building materials are part of the building environment and supported on an underlying substrate prior to possible wet removal.

The present disclosure further relates to a method to treat a building material which contains gypsum, Chrysotile asbestos and, optionally, other components, such as porous aggregate particulate as, for example, vermiculite, while part of a building structure. This is so as to transform the building material into a non-regulated material, with a silicate microencapsulation treatment composition that contains a polymer stable foaming agent system in an amount sufficient to provide a stable foamed treating composition that is capable of adhering to and soaking into the building material being treated. The system thereby provides a mode of applying a different method of microencapsulation prior to the silicate microencapsulation.

In accordance with the present disclosure, the present compositions and method are intended for microencapsulating Chrysotile asbestos material, asbestos materials generally, and Step 2 (second solution). The microencapsulated asbestos materials may then be suitable for wet removal, if required. The compositions comprise a unique combination of water, a chemical entity or low molecular weight polymer that will plasticize the TPE block co-polymer, and a high concentration of a non-ionic surfactant for the polymer component. This mixture is combined with the Step 1 components of the silicate microencapsulation system which contains additional water, two low concentrations anionic surfactants and sodium silicate. The sodium silicate is at or slightly above the desired pH range of 10-12.5 for polymeric silicic acid formation. This composition is first sprayed on the asbestos composition followed by a resonance time before spraying the microencapsulation setting agent which causes the sodium silicate to set. The setting agent has a small amount of phosphoric acid, an inorganic calcium salt, a thixotropic surfactant, and a small amount of poly DADMAC mixed with aluminum chlorohydrate. This setting composition is applied to the asbestos-containing materials after the plasticized polymer -silicic acid polymer composition has coated the Chrysotile fibers or other type asbestos such as Amosite containing building materials, in the form of a stable foam which permits absorption of from about 8 to 20 parts by weight of treating composition per part by weight of Chrysotile or Amosite asbestos in the material being treated.

The composition and methods of the present disclosure are suitable for the treatment of porous inorganic cementitious materials which contain asbestos fibers of Chrysotile or Amosite types to transform the building materials to microencapsulated materials. The present invention is especially useful for decontaminating Chrysotile asbestos fibers contained in gypsum-based building materials that have been previously applied to the structural components such as steel beams, decking and the like of buildings as coatings thereon to provide fire and heat resistance thereto.

The present disclosure describes a treating composition which is an aqueous solution or dispersion in the form of a stable foam as Step 1. The foaming agent system described herein has been unexpectedly found to be capable of carrying a high quantity of an aqueous system having agents capable of microencapsulating asbestos fibers on a nano-size scale while in place as part of a cementitious building material of adhering to said building material as applied delivering and transferring the aqueous system to the cementitious building material without loss of foam integrity and without substantial loss of the aqueous system to the building environment. The aqueous system may comprise a high concentration of a plasticized emulsified polymeric component with the alkaline component of the microencapsulation system as described herein below and in the above referenced applications.

The subject plasticized polymeric and surfactant compositions constitute a unique foaming agent system comprising both anionic and non-ionic functionality in an amount capable of maintaining the treating composition in the form of a polymer stable microencapsulating foam as fully described herein. The present foam may deliver an aqueous foamed system having a high non-ionic surfactant content in the plasticized polymer composition and a dual anionic surfactant from the two surfactants in the mixture of the plasticized SEE/PS block copolymer identified in US 7,329,355 Bl to Burns et.al., incorporated fully herein by reference, and an alkaline silicic acid microencapsulation component. The plasticizing agent is selected from various types of low molecular weight branched polymers.

The foaming agent system selected for use in the present treating compositions must be capable of imparting several critical properties to the treating compositions. For example, the selected foaming agent system must enable the treating composition to form a stable foam using equipment which is convenient for field operations. As used in this specification and claims, the term "stable foam" is meant to define a relatively dense foam (density of at least about 0.05 to 0.4 g/cc and preferably from about 0.05 to 0.15 g/cc) that is capable of existing in a highly alkaline environment. Further, the foaming agent system must be capable of forming a foam which is capable of adhering to cementitious building material and the like no matter what the orientation of the building material (e.g., horizontal or vertical, floor or ceiling). Still further, the foaming agent system must be capable of maintaining its integrity while it releases and provides its aqueous system to enter into the pores of the cementitious building material (e.g., the foam must be capable of existing for a sufficient time to permit penetration without drainage, as for example, at least 1 minute, preferably at least about 2 minutes and most preferably at least about 10 minutes after application of Step 1 to provide the aqueous treating composition that is capable of adhering to and soaking into the building material being treated rather than causing any significant drainage to the environment.

The foaming agent system also should provide the foamed treating composition with high cohesive and adhesive properties. In other words, the foamed treating composition should have enough cohesive strength to hold itself together as a mass with semi-solid (pseudoplastic) rheological properties, and enough adhesive strength to adhere to the asbestos-containing material being treated in the form of a relatively thick foam layer inside a surface active microencapsulation system. Thus, a foam treating composition in accordance with this invention should have sufficient adhesive strength to adhere as a layer of foam of from about 0.5 to about 2 inches in thickness to a building material disposed on a vertical or inverted building structure or an I-beam, with little if any run-off.

Because the treating compositions of the invention has a pH of 12 or less, the foaming agent systems that are suitable for use in the present treating compositions should be stable at high pH conditions. Accordingly, many agents that would be useful for generating a foam composition at a neutral or under acidic pH conditions, lose their functionality or decompose in some way causing them to not be suitable for use in the present invention. It might be appreciated that a foaming agent system that is unstable at high pH conditions, or which otherwise undergoes some decomposition, still might be acceptable for use, provided that the time required for such foaming agent system to decompose is longer than the time required for a foamed treating composition to be applied and soaked into the building material being treated. Thus, many decomposable foaming systems can be used if they are added to the treating composition immediately prior to foam formation and application to a building material. The foam treating composition of this invention is a stable foam prior to application.

The foam treating composition of this invention is a preferred foaming agent system because of its foaming and wetting properties. Thus, preferred foaming agent systems comprise a mixture of at least one agent having anionic functionality and at least one agent having non-ionic functionality. The relative amounts of the agent have non- ionic functionality and the agent having anionic groups should be added to the treating composition to provide a functional molar ratio of from about 500:1 to 1: 1 preferably from about 50:1 to 10:1, and most preferably from about 20:1 to 5: 1. The exact ratio to be used with a particular treating composition will depend on the components of the treating composition as well as the equipment being used to spread the foam and can be determined by small trial run. The term functional group, as used herein and in the appended claims, refers to the chemical function group(s) contained within a molecule. The molecule may be of a small, relatively simple structure or may be polymeric and each molecule may have one or more than one functional group within its molecular structure. The mixture of non-ionic and anionic foaming agent system may be added to the treating composition in amounts up to about 30% by weight based on the weight of the total composition. However, for a typical treating composition in accordance with the present invention, the foaming agent system usually comprises no more than about 20% by weight of the total composition.

The present foaming system must further include at least one non-ionic surfactant. These agents are believed, to not be limiting, to provide the driving force which enables the treating composition to be released into the pores against the force of gravity during its application to a porous building material. Not all agents provide the necessary low contact angle/high surface tension properties required of the present foaming agent systems. They may also provide corrosion protection to the steel that holds the asbestos fiber cementitious material.

Other Highly Hazardous Specialized Chemicals

The chemical known as biphenyl consists of two benzene rings tied together with a single carbon-carbon bond. It is not necessarily hazardous. A polychlorinated biphenyl (PCB) (Figure 5) is an organic chlorine compound with the formula PCB'S were once widely used as dielectric, heat transfer, coolant fluids in electrical devices and for carbonless copy paper. PCB's have a long lasting service life and are still widely in use for dielectric and heat transfer applications even though their manufacture has declined drastically since the 1960s, when a host of health problems were identified. Because of PCBs' environmental toxicity and classification as a persistent organic pollutant, PCB production was banned by the US Congress in 1979 and by the Stockholm Convention on Persistent Organic Pollutants in 2001. The International Research Agency on Cancer (IRAQ, rendered PCBs as definite carcinogens in humans. According to the EPA, PCBs cause cancer in animals and are probable human carcinogens. Many rivers and buildings including schools, parks, and other sites are contaminated with PCBs, and there have been contaminations of food supplies with the toxins.

Polychlorinated biphenyls are mixtures of up to 209 individual chlorinated compounds (known as congeners). There are no known natural sources of PCBs. PCB compounds are pale-yellow, viscous hydrophobic liquids with extremely low water solubility (around 0.0027-0.42 ng/L). They have high solubility in most organic solvents, a low vapor pressure at room temperature. They have dielectric constants of 2.5-2.7, very high thermal conductivities, and high flash points (from 170 to 380 °C). Density varies from 1.182 to 1.570 g/ml and other physical and chemical properties vary widely across the class. As the degree of chlorination increases, melting point and lipophilicity increase while vapor pressure and water solubility decrease. PCBs have no known smell or taste. Many commercial PCB mixtures are known in the U.S. by the trade name Aroclor.

PCBs do not easily break down or degrade, which made them attractive for industry. PCB mixtures are resistant to acids, bases, oxidation, hydrolysis, and temperature change. PCB's generate extremely toxic dibenzodioxin and dibenzofuran derivatives through partial oxidation at elevated temperature. Incineration at 1000 °C is destructive to PCBs. PCBs are fairly chemically unreactive, thus, they readily penetrate skin, PVC and latex, (natural rubber). PCB-resistant materials include Viton, polyethylene, polyvinyl acetate, butyl rubber, nitrile rubber, and Neoprene. Thermal desorption is highly effective technique for removing PCBs from soil.

Health effects that have been associated with exposure to PCBs include acne-like skin conditions in adults and neurobehavioral and immunological changes in children. PCBs are known to cause cancer in animals. PCBs have been found in at least 500 of the 1,598 National Priorities List sites identified by the EPA.

The EPA has chosen the best environmental clean-up method for PCBs is Solidification/ Stabilization where the waste solidification involves adding a binding agent, such as Portland cement, cement kiln dust, fly ash, a combination of the three or asphalt, to the waste to encapsulate the contaminants in an insoluble, less mobile, and less toxic solid matrix (U.S. EPA. /540/S-93/506, October). Solidifying waste improves its materials handling characteristics and reduces permeability to leaching agents by reducing waste porosity and exposed surface area. S/S processes utilize one or both of these techniques and are fundamentally different from other PCB remedial technologies in that they reduce the mobility of PCBs, but do not concentrate or destroy them (U.S. EPA 2000 EPA 542-R-00-010, September). Although often considered more appropriate for addressing inorganic contamination such as heavy metals, S/S has been used to successfully remediate organics (e.g. PAHs, dioxins) including PCBs at several sites ((U.S. EPA 2009. EPA/600/R-09/148, U.S. EPA, National Risk Management Laboratory, Office of R&D, November.) (Environmental Security Technology Certification Program (ESTCP) 2009. ESTCP, Project ER- 200510, May.)) In US EPA 1993, Technical Resource Document EPA/530/R93/012, June, the EPA suggests traditional cement and pozzolanic materials have yet to be shown to be consistently effective in full scale applications treating wastes high in O&G, surfactants, or chelating agents without pretreatment. S/S processes are often divided into the following broad categories: inorganic processes (cement and pozzolanic) and organic processes (thermoplastic and thermosetting). Generally speaking, in terms of chemistry, micro-procedures based on nanotechnology are often much more successful than macro-procedures or encapsulation and Solidification Stabilization; hence microencapsulation should be much more successful than macroencapsulation or Solidification Stabilization. The microencapsulation information discussed regarding Figures 1A, 2, and 3 and Table 1 were extremely successful in breaking down extremely hazardous chemical and biological warfare agent simulants followed by microencapsulation of the less hazardous oxidized components.

Other types of hazardous chemicals could possibly be stabilized for the long term using superior methods of microencapsulation techniques. Numerous inorganic compounds (pozzolanic) or more explicitly numerous heavy metals that have the capacity to form insoluble microencapsulated minerals or salts are one example Organics are divided up among Volatile Organic Compounds (VOCs) which include most organics and SemiVolatile Organic Compounds (SVOCs) such as many of the PCBs. Typical compound classes tested for SVOCs include, Poly Aromatic Hydrocarbons (PAHs), PCBs, Pesticides and Herbicides, Dioxins, Phthalates, Phenols, and a host of others organic compounds. In food safety applications, the following solvents are extracted: Pesticides, Herbicides, Contaminants, Adulterants, Veterinary Residues, Aflatoxins, and Mycotoxins. Other methods of classifying waste types ties them to the industry where they are used such as drilling mud wastes which could possibly be microencapsulated.

These are just a few of the new areas of work that need to be performed with this new superior technology called microencapsulation. For example, PAH's (Figure 6) are cyclic aromatic rings with reactive "bay" region sites between two carbons that could form a very toxic molecule with an oxide, diol or epoxide bond on the two adjacent carbons arrowed in Figure 6. PAHs are relatively high molecular weight solids with low volatility, relatively insoluble in water and soluble in many organic solvents. Most can be photo-oxidized and degraded to simpler substances.

The performance effectiveness of S/S technologies is most often measured using teachability tests: Synthetic Precipitation Leaching Procedure (SPLP) or Toxicity Characteristics Leaching Procedure (TCLP). A wide range of other performance tests may need to be performed in conjunction with microencapsulation or the S/S treatability studies of the treated material. These include total waste analysis for organics, permeability, unconfined compressive strength (UCS), treated waste and or leachate toxicity endpoints, and freeze/thaw and wet/dry weathering cycle tests, Treatability studies should be conducted on replicate samples from a representative set of waste batches that span the expected range of physical and chemical properties to be encountered at the site.

Example 1 - Asbestos

Samples of the microencapsulating product modifications were prepared by Clean Tech Innovations, LLC in Bartlesville, OK and sent to EMSL Analytical, Inc. in Cinnaminson, NJ for asbestos testing.

Three aliquots of NIST amosite (grunerite) asbestos were placed in a clean unused glass jars. Step 1 was the emulsion and was poured into the glass jar containing the amosite asbestos. The sample was stirred to coat the asbestos and allowed to setup for 5 minutes before Step 2 of the liquid was added and then thoroughly mixed together with a stir rod to ensure fiber coating. The resulting substance was left to dry in a biosafety cabinet for 3 days. The samples were split and one sample was provided to the asbestos division and one sample to the material science lab.

In preparation for transmission electron microscopy (TEM) and polarized light microscopy (PLM) analysis, the sample material was transferred to a crucible and prepared via a modified EPA/600/R-93/116. The sample was placed in a muffle furnace at 480 °C for 8 hours until the sample was completely ashed to a fine powder. The ash was then treated with 1 N HC1 acid, to remove any carbonates and the residue was filtered down onto a 0.4 um polycarbonate (PC) filter. The filter was dried in a drying oven until the residue was dry. A portion of the residue was the scraped with a scalpel blade and put into a small centrifuge filled with laboratory grade isopropyl alcohol. The tube was ultra-sonicated for 1 minute and a small aliquot of the suspension was placed onto a carbon coated copper TEM grid. The remaining residue was left on the PC filter for PLM analysis.

The sample was analyzed using a JEOL 100 CXII analytical transmission electron microscope at 20,000X and a Leica PLM microscope to determine if the microencapsulation process altered the asbestos in any way. Amosite asbestos (grunerite) is a mineral in the amphibole group with formula Fe ₇ Si ₈ 02 ₂ (OH) ₂ . Both the standard and the processed sample were analyzed by energy dispersive X-Ray analysis (chemistry), selected area electron diffraction (crystal lattice), and PLM. In each analysis, the amosite was still identifiable as grunerite asbestos, proving that the process had not altered the asbestos Fe ₇ Si ₈ 0 ₂₂ (OH) ₂ tip.

The sample was prepared by the EMSL Asbestos Laboratory and submitted as documented in attached appendix. The material, once received in the Materials Science Laboratory, was dried in several ways including drying for 72 hours at ambient temperature and humidity, at 70°C and at 105°C. The ambient and 70°C samples did not dry sufficiently for SEM analysis. The sample dried at 105°C was found acceptable for analysis. Analysis of the sample by SEM revealed that the majority of the asbestos fibers and bundles were encapsulated in, or contained in a thin coating of, the applied product. These structures may represent a friable material.

Example 2 - System Expansion - Heavy Metals

This experiment is intended to generate results demonstrating how the microencapsulation procedure might perform if the substance being microencapsulized were a toxic heavy metal. Table 2 shows the reduced levels of extractable Cd ⁺² after microencapsulation with the Stepl and Step 2 additives followed by a TCLP extraction. The solutions (up to 300 ppm Cd ⁺² ) treated in a 1:1 :1 ratio of Metal Solution/Step 1 /Step 2 volumes were micro encapsulated to leachable levels that fall within the EPA RCRA Toxicity limit of 1 ppm or less for land filling. If a 1: 1 : 1 ratio does not provide a 1 ppm or less M concentration, using a 1:2:2 or a 1:3:3 micro encapsulation ratio will probably provide leachability of less 1 ppm meeting EPA's RCRA Toxicity limit up to about 500 ppm of Cd ⁺² in solution. The 1:3:3 ratios have lower leachability levels than the 1:2:2 ratio's and there is an aqueous Cd ⁺² level above 500 ppm that can be treated to below the regulatory level, but it is not apparent from the data.

6 161.67 1:3:3 0.18 99.8887

7 264.50 1:1:1 0.80 99.6975

8 264.50 1:2:2 0.42 99.8412

9 264.50 1:3:3 0.28 99.8941

10 377.30 1:1:1 1.60 99.5760

11 377.30 1:2:2 0.62 99.8357

12 377.30 1:3:3 0.46 99.8781

13 485.10 1:1:1 2.20 99.5470

14 485.10 1:2:2 0.80 99.8351

15 485.10 1:3:3 0.40 99.9175

16 848.00 1:1:1 15.9 98.125

17 2,150 1:1:1 40.3 98.126

18 2,150 1:2:2 16.6 99.228

19 2,150 1:3:3 14.3 98.345

20 10,220 1:1:1 179 99.249

21 10,220 1:2:2 86.6 99.153

22 10,220 1:3:3 62.5 99.389

23 36,600 1:1:1 500 98.634

24 36,600 1:2:2 281 99.232

25 36,600 1:3:3 163 99.555

Although impressive reductions (most >99%) were obtained for highly concentrated Cd ⁺² solutions up to 36,600 ppm, anything above 500 ppm is not eligible for landfilling since the EPA RCRA leachable toxicity limit is above 1 ppm. Now, one could evaluate at a reagent concentration of 1:4:4, but at some point it becomes a question of economics. The original aqueous concentration of Cd ⁺² is plotted against the data after TCLP resulting in the appearance of a linear relationship as shown in graphical Figure 7 shows R ² values of 0.9932 - 0.9883, indicating a good fits.

Table 3 shows the similar reduced levels of extractable Cr ⁺⁶ after microencapsulation with the Step 1 and Step 2 additives followed by TCLP extraction. The solutions (up to 500 - 800 ppm Cr ⁺⁶ ) treated in a 1:1:1 ratio with Step 1 and Step 2 additives were microencapsulated to leachable levels that fall within the EPA RCRA Toxicity limit of 5 ppm for landfilling. Using a 1:2:2 or a 1:3:3 microencapsulation ratio provides improvements although with this data it is unclear as to the upper concentration limit of contamination treatment between 400 - 1430 ppm. Table 3. Reduction in Aqueous Cr ⁺⁶ Concentration After

Microencapsulation V Vith Different Step 1 and Step 2 Additive Ratios.

Microencapsulation Ratio Cr ⁺⁶ TCLP Micro-

Entry Aqueous Ct ⁺⁶ of Extracted from Encapsulation Number Cone, ppm Aqueous Cr ⁺⁶ to Micro- Efficiency, %

Step 1/Step 2 Encapsulation

RCRA TCLP Limit = 5 p pm

1 35 1 1 :1 0.020 99.9429

2 35 1 2:2 0.006 99.9829

3 35 1 3:3 0.010 .99.9714

4 130 1 1 :1 0.034 99.9738

5 130 1 2:2 0.014 99.9892

6 130 1 3:3 0.020 99.9846

7 19 1 1 :1 0.034 99.9821

8 190 1 2:2 0.020 99.9895

9 190 1 3:3 0.020 99.9895

10 280 1 1 : 1 0.042 99.9850

11 280 1 2:2 0.022 99.9900

12 280 1 3:3 0.018 99.9936

13 400 1 1 : 1 0.046 99.9885

14 400 1 2:2 0.032 99.9920

15 400 1 3:3 0.028 99.9930

16 1430 1 1 :1 9.2 99.357

17 1830 1 1 :1 28.90 98.421

18 1830 1 2:2 15.90 99.131

19 1830 1 3:3 9.86 99.461

20 9010 1 1 :1 139.0 98.457

21 9010 1 2:2 75.0 99.168

22 9010 1 3:3 47.3 99.475

23 22,000 1 1 :1 382 98.264

24 22,000 1 2:2 215 99.023

25 22,000 1 3:3 145 99.341

Although impressive reductions (>99%) were obtained for highly concentrated Cr ⁺⁶ solutions up to the range between 400 - 1,430 ppm, the samples from 1,430 and up are not eligible for landfilling since the EPA RCRA Toxicity limit is above 5 ppm. The original aqueous concentration of Cr ⁺⁶ is plotted against the data after TCLP showing a linear relationship in Figure 8.

Table 4 shows the similar reduced levels of extractable Pb ⁺² after microencapsulation with the Step 1 and Step 2 additives followed by TCLP extraction. The solutions treated in a 1:1 :1 ratio with Step 1 and Step 2 well beyond 620 ppm Pb ⁺² and were micro encapsulated to leachable levels that fall within the EPA RCRA Toxicity limit of 5 ppm for landfilling. Lead levels of 10,000 or more would probably pass the 5 ppm RCRA standard using a 1:2:2 and a 1:3:3 microencapsulation ratio may extend the leachability of levels of aqueous contaminants around 15,000 to less that 5 ppm meeting

EPA's RCRA Toxicity limit up to about 500 ppm of Pb ⁺² in solution.

Pb ⁺² solutions up to 32,600 ppm, these higher concentrations are not eligible for landfilling since the EPA RCRA Toxicity limit is above 5 ppm. The original aqueous concentration of Pb ⁺² is plotted against the data after TCLP showing a linear relationship in Figure 9. Although impressive reductions (>99%) were obtained for highly concentrated Pb ⁺² solutions up to 32,600 ppm, these higher concentrations are not eligible for landfilling since the EPA RCRA Toxicity limit is above 5 ppm. The original aqueous concentration of Pb ⁺² is plotted against the data after TCLP showing a linear relationship in Figure 9.

Example 3 - System Expansion - Hydrocarbons Contaminated Soil

Methods

The purpose of this Example was to generate data to represent the most probable outcomes that might occur when a given volume of characteristic waste contaminated soil of known contaminant concentrations is treated with various concentrations of Step 1 and Step 2. The analytical hydrocarbon test results demonstrate that the Step 1 and Step 2 recommended treatment rates used at the different soil contamination levels meet the regulatory standards. Therefore, these results validated the Step 1 and Step 2 treatment rate vs. contaminant concentration curve used for making the treatment recommendations for the contaminated soils.

Characteristic wastes generally result from transportation fuels, lubricants and crude oils as differentiated from listed wastes that are considered hazardous and must be handled differently. Ideally, the selected Step 1 and Step 2 treatment rate should provide residual leachable levels of contaminant concentrations below regulatory risk-based standards. The three contaminants selected for evaluation are gasoline, diesel and crude oil. These contaminants were evaluated in both silty loam and clay soils. According to the study, the EPA NCP Subpart J Product Schedule testing was not necessary for the Step 1 and Step 2 additives. For soil remediation of gasoline or diesel spills in Oklahoma, the Department of Environmental Quality (DEQ) states the contaminants of concern for groundwater are primarily TPH and BTEX at the following levels: Benzene <0.04 ppm, Toluene <20.00 ppm, Ethylbenzene <15 ppm, and Xylenes <167. Where groundwater and surface water impacts are not of concern at the site, 50 ppm TPH is an appropriate cleanup level and BTEX analysis is not necessary. Likewise at an industrial site, generally 500 ppm TPH is acceptable for gasoline and 2500 ppm TPH for diesel. Petroleum contaminated soil with TPH < 1000 ppm may go to any landfill permitted to accept non-hazardous industrial solid waste. Above 1000 ppm the landfills must be equipped with synthetic liners and leachate collection systems. These are regulatory guidelines only and for specific situations, one should consult the appropriate regulation or DEQ representative. The Step 1 and Step 2 additives are unique since contaminates are solvated as liquids or emulsions in the liquid Step 1 and converted into a solid silicate matrix quickly after coming into contact with the Step 2 additive. As the silica microcapsules dehydrate, the silica irreversibly shrinks increasing the packing density and the pore diameters diminish firmly holding the contaminants in place. Not only is the contaminant strongly held in the microencapsulate, but the miroencapsulate could be considered a nanoabsorbent of the contaminant. Since these products are on a micro level (50-100 nm), they are superior to the classic stabilization/immobilization technologies based on cement-like materials, but they also have characteristics of absorbents that can permanently lock contaminants into the matrix. There are no specific test methods designed for absorbents other than the Paint Filter Test (EPA Method 9095B) for landfill acceptance. The TCLP extraction and subsequent filtration procedure was originally designed for RCRA metals and selected organics extraction and analysis by the EPA. For more details, see 40 CFR §261.24 to explain its derivation from toxic (characteristic wastes) wastes. TCLP helps identify wastes likely to leach concentrations of contaminants that may be harmful to human health or the environment. TCLP was adopted as a standard means of characterizing the hydrocarbon immobilization capacity of the TERRACAP additives. It is an aggressive procedure that involves a 20: 1 dilution and 18 hr agitation of samples to produce a leachate. The objective was to use the procedure to generate worst-case scenario leachate that could undergo laboratory testing. Hydrocarbon analyses performed on TCLP leachates consistently range from <1— 20 mg/1, well below the 50 ppm limit.

Mixing and Delivery System

The application soil mixing apparatus for soil contamination was a commercial grade Kitchen Aide Professional 600 mixer affixed with three conical spray nozzles for delivery of the contaminant, the Step 1, and the Step 2 while mixing. The spray nozzles were connected to 100 ml stainless steel reservoirs pressurized to 40 psi using air as the delivery mechanism. A whip blade was used on the counter rotational shaft mixer to blend the soil, contaminant, Step 1 and Step 2.

Laboratory Treatment Procedure

The general laboratory treatment procedure for soil remediation was as follows:

1. Mix a predetermined soil in the blender to a fine consistency over a 5 minute period.

2. Transfer a predetermined volume of contaminant to its reservoir and use 40 psi air pressure to contaminate the soil with the hydrocarbon and allow to mix for 5 minutes after addition was complete.

3. Remove a 100 g control sample of contaminated soil.

4. Transfer Step 1 and Step 2 into the separate reservoirs. 5. Spray Step 1 using an air pressure of 40 psi on the reservoir and allow to mix with the contaminated soil for 5 minutes after the addition was complete.

6. Spray Step 2 using air pressure of 40 psi on the reservoir and allow it to mix for 5 minutes after the addition was complete.

The quantities of soil, contaminant, Step 1 and Step 2additives, and water are shown in Table 5. The contaminant and soil weight total were 1,100 g. The Step 1 and Step 2additives were always added in equal volumes to the contaminant. The degree of mixing is very important when adding the Step 1 to the hydrocarbon contaminated soil. Mixing was the primary variable in determining the quality of desorption contact between the surfactant system of the Step land the hydrocarbon contaminant. The level of mixing achieved when adding the Step 2 to the mixture is important to rapidly achieve a homogenous mixture with a neutral pH that converts the silica in to a sand-like particle within seconds of contact. The time between addition of the Step 1 and Step 2 additive was five minutes allowing for emulsification of the hydrocarbon before addition of the Step 2.

In the preliminary experiments, it was realized that the Step 1 and Step 2 additives would require dilution with water in order to adequately cover the soil particles. This is related to and just as important as mixing. Best results are obtained when the soil is moist, but not muddy as this could cause operational problems in the field with the equipment. The soil was treated with the Step 1 and Step 2 concentrates only at the highest contaminant concentration where sufficient Step 1 and Step 2 volume was present to wet the soil particles. Otherwise, there was always a dilution and the optimum dilution was generally determined by operational and he TPH (BTEX) results. When the Step 1 of a given dilution was added to the soil with mixing, a level of fluidity was obtained with the soil. Once the Step 2 was added this fluidity disappears and a drying effect is observed. Generally at 200,000 ppm contaminant level, the 1: 1 dilution ratio is recommended. At the 100,000 ppm contaminant, the 1:2 dilution ratio is preferred. For 50,000 - 4,000 ppm, contaminant, a 1:3 dilution ratio is preferred. Although 1:4 dilution ratios may be used, suitable results may be obtained with 1:3 dilution ratios. A plot of Step 1 and Step 2 additive concentrations were varied with respect to each known volume of the contaminant concentrates vs Step 1 and Step 2 additive treatment rate is shown in Figure 10.

Numerous other details were explored and worked out prior to the start of the testing program such that a consistent procedure could be used throughout the testing program. Examples of these are: choosing the best spray nozzles (cone), mixing

Most of the data analysis process was as follows: A sample of the micro encapsulated material was extracted using the TCLP procedure. Following the extraction, the filtrate was separated by vacuum filtration according to the procedure. The filtrate was submitted to Green Country Testing in Tulsa, OK for GC analysis to determine TPH by EPA Method 8015m for either DRO, GRO or LRO. BTEX values were determined by EPA method 8020 if necessary. BTEX occurs primarily in gasoline, diesel and crude oil. The controls were not TCLP extracted. TPH and BTEX analysis were performed directly on the control soil samples to establish the level of sample's contamination. Sampling was performed to determine the average levels of contaminants in the waste that were to be assessed. It is important to recognize that most incorrect chemical assessments of waste are due to poor or incorrect sampling. But, generalized sampling recommendations are not possible, since they depend on the consistency of any tested property throughout the material to be tested. Sampling the soil for the TCLP extraction and the subsequent TPH and BTEX analysis is perhaps where the largest level of error could be introduced, especially with the control samples. There is a small level of absorption by hydrocarbons on soil that may not be extracted making soils more difficult to analyze according to Brian Duzon, POC at Green Country Testing. As the contaminant is introduced by spray onto the soil or clay, a certain portion also coats the mixing bowl and the mixing whip. Volatility was a concern with samples such as the gasoline. At the higher contaminant concentrations, the soil was wet with hydrocarbon and it did not take long after mixing to visually see free hydrocarbon contaminant settle in the mixing bowl or container. Sampling probably explains much of the differential between the targeted contaminant concentration levels and that value determined by analysis. Those values determined by analysis are generally fairly accurate for that small sample, although the real value is accurate for the amount of contaminant added in the overall system less might be lost to the mixing and spray equipment. After the Step 2 was added to the mixture for micro encapsulation, the soil during mixing became more homogeneous and had a drier appearance. Sampling contributed much less to error on the Step 1 and Step 2 treated samples because there was no presence of any free contaminant on the soil or on the surface of the TCLP extraction water.

Results and Discussion

Table 6 shows the results of diesel contaminated silty soil micro encapsulated by the Step 1 and Step 2 additives to reduce leachability. The control TPH and BTEX values are from the same sample. The controls were not TCLP extracted, rather extracted with 50/50 methylene chloride/ acetone and analyzed according to EPA 8015 and 8020 as received. These values varied greatly from the intended calculated contamination levels. This is undoubtedly due to settling and pooling during sampling, and during the mixing process, the loss of oil left on the blender whip and container and spray equipment. However, nature is variable as well. The treated samples are each from different contamination runs. Originally large batch runs were made and combined from which the micro encapsulation runs were made. Due to the significant amount of non- soil absorbed contaminant at the higher contaminant concentrations, the contaminant formed gradients in the storage container. Therefore, this technique was abandoned in favor of making fresh contaminated soil for each micro encapsulation experiment followed by addition of the first (Step 1) solution and the second (Step 2) solution.

Note that all of the micro encapsulation results show leachability below the DEQ levels of 50 ppm TPH, <0.04 ppm benzene, <20.00 ppm toluene, <15.00 ppm ethylbenzene, and < 167 pp, xylenes for diesel in silty soil. The majority of the micro encapsulated samples analyzed as Non Detect (ND), meaning they were below the levels indicated in the appropriate footnote. The entry for 36-6c indicates < 0.11 ppm for ethylbenzene results from the triplicate average of 0.328 for one analysis and two analysis results that were ND or < than 0.05 therefore the average of the three results is <0.11. Note, entry number 5c was also analyzed by EPA 8015 without TCLP to establish the actual amount of hydrocarbon that was microencapsulated in the soil sample and found to be 6,500 ppm.

Table 7 shows the results of gasoline contaminated silty soil. The 10,000 ppm run was eliminated from all of the following tests since there was not much difference in material concentrations from 0.5 lb/ton to 0.75 lb/ton treatment rate. Gasoline may have higher concentrations of BTEX than diesel and sometimes the crude oil. Note the TPH levels on the micro encapsulated samples are all under 50 ppm. However, the benzene was slightly out of regulatory specifications at the two highest contaminant levels (highlighted), but at a 1 :2 dilution, it was within the regulatory levels. This suggests that for gasoline, a 1:2 dilution level for is preferred at the higher concentrations and at the 100,000 - 200,000 ppm level for gasoline, a treatment rate of 4.5 gal/ton might be required. The preferred dilution ratios are highlighted.

Table 7. Step land Step 2 Additive Treatment of Gasoline Contaminated Silty Soil.

1. Stepl & Step 2.

2. ND = Non-dedect levels for BET (0.05 ppm) and X (0.15 pp).

Note: The preferred dilution ratios are bolded.

Table 8 shows the results of Bartlesville crude oil contaminated silty soil. Note the TPH levels on the microencapsulated samples are all under 50 ppm as well as the BTEX levels are all within the regulatory standards of <0.04 ppm benzene, <20.00 ppm toluene, <15.00 ppm ethylbenzene, and < 167 pp, xylenes.

Note: The preferred dilution ratios are bolded.

Table 9 shows the results of diesel on clay soil. The TPH levels microencapsulated samples are all under 50 ppm as well as the BTEX levels are all within the regulatory standards of <0.04 ppm benzene, <20.00 ppm toluene, <15.00 ppm ethylbenzene, and < 16 ppm, xylenes.

Table 9. Step 1 & Step 2 Additive Treatment of Diesel Contaminated Clay Soil.

1. Stepl & Step 2.

2. ND = Non-dedect levels for BET (0.005 ppm) and X (0.015 pp).

3. ND = Non-dedect levels for BET (0.05 ppm) and X (0.15 pp). I Note: The preferred dilution ratios are bolded.

Table 10 shows the results of gasoline on clay soil. As with gasoline on silty soil, The benzene levels are above regulatory levels at the 200,000 and 100,000 concentrations. The 100,000 might be reduced by further dilution of the Step 1 & Step 2 additive as was the case for silty soil.

Table 10. Step 1 & Step 2 Additive Treatment of Gasoline Comtaminated Clay Soil.

1. Stepl & Step 2.

2. ND = Non-dedect levels for BET (0.05 ppm) and X (0.15 pp).

Note: The preferred dilution ratios are bolded.

Table 11 shows the results of crude oil on clay soil. Again, note the TPH levels on the microencapsulated samples are all under 1.4 ppm as well as the BTEX levels are all within the regulatory standards of <0.04 ppm benzene, <20.00 ppm toluene, < 15.00 ppm ethylbenzene, and < 167 pp, xylenes.

Significant Technical Achievements

The most significant technical achievement was the TPH of hydrocarbon contaminated soils are reduced to < 50 ppm according to the concentration plot shown in Figure 8. The R2 = 0.9824 for a power law algorithm of F(x) = 16.67x1.75 for the relationship. This was true in both sandy loam and clay soils for diesel fuel and crude oil. Contaminates are desorbed by the Step 1 and quickly converted into a solid silicate matrix after contacting the Step2 additive. As the silica microcapsules dehydrate, the silica irreversibly shrinks, increasing the packing density and the pore diameters diminish firmly holding the contaminants in place. Since the pore size overlaps that of nanoparticles, the Step 1 and Step 2 additives are considered a nano absorbent that is superior to the classic stabilization/immobilization technologies.

Of notable achievement, the lab data generated met ODEQ regulations for benzene in all contaminants except at the high TPH end of gasoline. For 200,000 ppm gasoline, benzene/sandy loam soil, was reduced to 3.18 ppm (ODEQ <0.04 ppm), but at 100,000 ppm gasoline, it was 0.021 ppm. In clay, the benzene was 2.696 ppm at 200,000 ppm contaminant and 0.129 ppm at the 100,000 ppm gasoline concentration. Below 100,000 all benzene regulatory requirements were achieved. Figure 8 is a standard "one fits all" curve that accommodates 99% of the data. High concentrations of gasoline may be treated to regulatory levels by a slight volume increase in the amount of Step 1 & Step 2 used.

Example 4. Methods and Assumptions

This example is an attempt to contaminate subsurface soil and microencapsulate the hydrocarbon is a soil pack core.

Apparatus

The core apparatus consisted of a 3 inch inside diameter by 10 inch long polyvinyl chloride pipe. The pipe fits into a standard drilling mud fluid loss testing apparatus with top and bottom caps that were pressure fitted by means of an adjustment screw against the ends of the pipe. Cork gasket was used to seal the ends of the pipe into the caps. The core was mounted in the vertical position. The top cap had an inlet and a dispersion plate for the purpose of minimizing channeling. The bottom had a liquid exit where the fluid was collected and analyzed. The fluid loss apparatus originally had a steel cylinder, but it was very difficult to remove the core intact using the steel cylinder. It was possible to hydraulically remove the core from the PVC core holder without disintegration.

Core Soil Packing and Fluid Mixing

The dry (moisture) contaminated soil prepared using the same procedure described in Example 3 was packed into the core in four equal amounts (425 g) using a screw attached to a plunger equal in diameter to the core in the fluid loss apparatus. At the end of this process the top of the packed soil was at the top end of the core. The total soil volume of the core was 1,700 g. In previous discussions, mixing was the primary variable attributable to determining the quality of desorptive contact between the surfactant system of the Step 1 and the hydrocarbon contaminant. The dilution conclusions from Example 3 regarding Step 1 and Step 2 dilution were applied to here without further experimentation primarily because there was a lot of soil to contact evenly. Mixing is also important when pumping the Step 2 into the core to rapidly achieve a homogenous mixture with a neutral pH that converts the silica into a sand-like particle within seconds of contact. The bottom line is that mixing in a core is more or less up to chance based on the homogeneity of the packed soil.

Pumping Procedure

Pump pressure was minimal and it was determined not to be a variable in this experimental setup. The pump rate was 7 ml/minute for these experiments. Low pump rates are desirable in the field so as not to fracture the subsurface. Preliminary runs helped establish the optimum pump speed, the optimum Step 1 and Step 2 additive dilution factor and to get comfortable with the setup. Predetermined amounts of diluted Step 1 and Step 2 additives at established concentrations relative to the contaminant concentration were injected into the core. Breakthrough at the bottom of the core is important in establishing the volume of Step 1 and Step 2 additives pumped. The Step 1 and Step 2 are always each added in equal amounts to the contaminant. A problem was observed when injecting a liquid into a soil core, the core becomes saturated as the fluid face moves across the core. A lot more liquid was required to contact the lower levels of the core before an acceptable concentration of the Step land Step 2 additives actually contact the bottom of the core. This level of soil wetting does not occur in the surface soil remediation experiments in Experiment 3. Also, in the real world, the subsurface core has an infinite length depending on the height, width and the volume of fluid injected into a subsurface area. There was no collection at the end of the core so to speak. This paradigm shift makes a significant difference in the outcome. Other concerns in subsurface treatments involve ionic attraction or adherence of the microencapsulation components onto the soil surface area and porosity as the fluid moves through the core or subsurface area. For these reasons, the concentration of Step 1 and Step 2 additives was increased by a factor of 5 per weight of soil compared with the results in Example 3. The quantity of the Step 1 was 160 g and the Step 2 was 160 g, each diluted with an equal amount of water. The pumping procedure was:

1. Pump 160 g of Step 1 diluted with 160 g of water.

2. Pump air for 30 minutes followed by 25 g of water to act as a flush.

3. Pump 160 g of Step 2 diluted with 160 g of water.

4. Pump air until no more liquid exited the cylinder.

5. Let the core set 12 hours before hydraulic removal.

The cores were removed and sections sliced from the top and bottom of the cores for TCLP extraction followed by TPH, BTEX analysis. The diesel contaminant concentrations evaluated were 4000 and 100,000 ppm.

Results and Discussion

Numerous practice runs were made to identify the various parameters of importance. The experiments focused on two concentrations of diesel contaminated soil, 10,000 and 4,000 ppm. The packed core generally accepted the 320 g of diluted Step 1 and around 160 g of the diluted Step 2 before the liquid exited the core. Liquid ceased dripping from the cylinder at about 475 ml. Therefore the core retained approximately 190g of injected materials. Coincidentally, the volume of water in the concentrated Step 1 and Step 2 additives is about 180g suggesting that most of the solids from the additives probably remained in the core and the liquids (water) exited. The pH of the exit fluid was neutral.

The soil core was removed from the core holder for observation and analysis. Plugging was not observed during these initial tests. When the diesel contaminated core was removed, it appeared the Step 1 and Step 2 additives were fairly evenly distributed in the core matrix. A slight white color was observed in some areas indicating some channeling had occurred. Hydrocarbon desorption from the soil is important, therefore Step 1 and Step 2 dilution factors are critical to optimize soil coverage. The soil nearest the inlet received all of the fluid and the soil at the bottom of the core likely received active Step 1 and Step 2 components at lower concentrations. Channeling was always a concern. The soil in the core did not have a diesel odor. It is believed that the diesel fuel in the core had a tendency to float upward because of density, but it was microencapsulated because it was not found in the exit water. The core was sliced at the top and at the bottom for sampling, TCLP and analysis along with the water sample. Note the TPH was between 4 - 5 ppm in both core examples and benzene was a non- detect. The water sample contaminant levels were ND. These results are depicted in Figure 11.

The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processes and manufacturing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the invention herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the claimed invention.

It is to be understood that the terms "including", "comprising", "consisting" and grammatical variants thereof do not preclude the addition of one or more components, features, steps, or integers or groups thereof and that the terms are to be construed as specifying components, features, steps or integers.

If the specification or claims refer to "an additional" element, that does not preclude there being more than one of the additional element.

It is to be understood that where the claims or specification refer to "a" or "an" element, such reference is not be construed that there is only one of that element.

It is to be understood that where the specification states that a component, feature, structure, or characteristic "may", "might", "can" or "could" be included, that particular component, feature, structure, or characteristic is not required to be included.

Where applicable, although state diagrams, flow diagrams or both may be used to describe embodiments, the invention is not limited to those diagrams or to the corresponding descriptions. For example, flow need not move through each illustrated box or state, or in exactly the same order as illustrated and described.

Methods of the present invention may be implemented by performing or completing manually, automatically, or a combination thereof, selected steps or tasks.

The term "method" may refer to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the art to which the invention belongs.

The term "at least" followed by a number is used herein to denote the start of a range beginning with that number (which may be a ranger having an upper limit or no upper limit, depending on the variable being defined). For example, "at least 1" means 1 or more than 1. The term "at most" followed by a number is used herein to denote the end of a range ending with that number (which may be a range having 1 or 0 as its lower limit, or a range having no lower limit, depending upon the variable being defined). For example, "at most 4" means 4 or less than 4, and "at most 40%" means 40% or less than 40%. Terms of approximation (e.g., "about", "substantially", "approximately", etc.) should be interpreted according to their ordinary and customary meanings as used in the associated art unless indicated otherwise. Absent a specific definition and absent ordinary and customary usage in the associated art, such terms should be interpreted to be ± 10% of the base value.

When, in this document, a range is given as "(a first number) to (a second number)" or "(a first number) - (a second number)", this means a range whose lower limit is the first number and whose upper limit is the second number. For example, 25 to 100 should be interpreted to mean a range whose lower limit is 25 and whose upper limit is 100. Additionally, it should be noted that where a range is given, every possible subrange or interval within that range is also specifically intended unless the context indicates to the contrary. For example, if the specification indicates a range of 25 to 100 such range is also intended to include subranges such as 26 -100, 27-100, etc., 25-99, 25- 98, etc., as well as any other possible combination of lower and upper values within the stated range, e.g., 33-47, 60-97, 41-45, 28-96, etc. Note that integer range values have been used in this paragraph for purposes of illustration only and decimal and fractional values (e.g., 46.7 - 91.3) should also be understood to be intended as possible subrange endpoints unless specifically excluded.

It should be noted that where reference is made herein to a method comprising two or more defined steps, the defined steps can be carried out in any order or simultaneously (except where context excludes that possibility), and the method can also include one or more other steps which are carried out before any of the defined steps, between two of the defined steps, or after all of the defined steps (except where context excludes that possibility).

^ Ψ

Thus, the present invention is well adapted to carry out the objects and attain the ends and advantages mentioned above as well as those inherent therein. While presently preferred embodiments have been described for purposes of this disclosure, numerous changes and modifications will be apparent to those skilled in the art. Such changes and modifications are encompassed within the spirit of this invention as defined by the appended claims.