WO2000078448A1

WO2000078448A1 - Encapsulant compositions, methods and devices for treating liquid spills

Info

Publication number: WO2000078448A1
Application number: PCT/US2000/017252
Authority: WO
Inventors: Anthony M. Pierce
Original assignee: SUSTAINABLE TECHNOLOGIES Corp
Current assignee: SUSTAINABLE TECHNOLOGIES Corp
Priority date: 1999-06-22
Filing date: 2000-06-22
Publication date: 2000-12-28
Anticipated expiration: 2001-12-22
Also published as: AU5633400A

Abstract

Described are preferred encapsulant compositions, devices and methods for treating liquid spills. Preferred compositions include a particulate superabsorbent polymer along with an agent for forming an interpenetrating polymer network upon contacting the aqueous spill to bond particles of the superabsorbent polymer together to form a unitary, removable mass. Preferred compositions also include a blend of at least two superabsorbent polymers, wherein one of the superabsorbent polymers absorbs water significantly faster than another. Devices for spray application of such encapsulant compositions include a canister adapted for forcibly spraying a particulate composition, and a powdered encapsulant composition as described contained in the canister. Methods for treating spills of liquids involve the application of encapsulant compositions as described.

Description

ENCAPSULANT COMPOSITIONS, METHODS AND DEVICES FOR TREATING LIQUID SPILLS

BACKGROUND OF THE INVENTION

The present invention relates generally to the containment and clean up of hazardous spills . In particular, the present invention relates to methods, compositions and devices for encapsulating spills of substances such as acidic or biologic spills. As further background, the containment of hazardous spills has been the subject of study for years. In many cases, containment is achieved utilizing a solid particulate material which is applied to the spill to absorb and encapsulate the hazardous material. Certain compositions including polymers have been suggested for use in treating aqueous spills. For example, U.S. Patent Nos. 4,383,868 and 4,578,119 are illustrative of this background to the invention. Despite some teaching in the area, there still exist needs for improved compositions, methods and devices for treating hazardous spills. The present invention addresses these needs . SUMMARY OF THE INVENTION Accordingly, in one aspect, the present invention provides an encapsulant composition for treating a hazardous spill, especially a hazardous aqueous spill, which includes at least one particulate absorbent, along with a polymer matrix forming agent for forming an interpenetrating polymer network between particles of the absorbent upon contacting the spill, such that the encapsulant composition exhibits the capacity to form a solid unitary mass upon absorbing the spill. In one preferred form, the encapsulant composition has a polymer matrix forming composition that includes a water soluble crosslinkable agent, for example a polyol such as polyvinyl alcohol, and a water soluble crosslinking agent for crosslinking the crosslinkable agent to form the polymer matrix, for example borax and/or boric acid. In the dry state, these materials are compatible as a stable, homogeneous, flowable mixture. When applied to an aqueous spill, dissolution of the crosslinkable agent and the crosslinking agent, and their subsequent interaction, lead to the formation of the interpenetrating polymer network which binds the absorbent particles (e.g. superabsorbent polymer particles) together to form a conveniently-handled, unitary solid mass.

In another aspect of the invention, it has been discovered that encapsulant compositions having improved absorption characteristics are provided when using a mixture of particles of two differing superabsorbent polymers, wherein one exhibits a relatively high absorption time and the other exhibits a relatively low absorption time. Thus, in another preferred embodiment, an encapsulant composition includes a first particulate superabsorbent polymer, the first superabsorbent polymer having a first absorption time, and a second particulate superabsorbent polymer, the second superabsorbent polymer having a second absorption time. In accordance with the invention, the second absorption time is at least about double (200% of) the first absorption time. In a more preferred form, the first superabsorbent polymer exhibits an absorption time sufficiently high that the polymer absorbs 70% of its total capacity for deionized water in less than about 1 minute, and the second superabsorbent polymer has an absorption time sufficiently low that it reaches 70% of its deionized water absorption capacity at some time point after 5 minutes. The first and second polymers are preferably polyacrylamide or polyacrylate superabsorbent polymers, and the encapsulant compositions can include mixtures thereof . In other embodiments, the present invention provides devices for encapsulating spills which include a pressurized canister containing the above-described encapsulant compositions, and having the capacity to dispense the encapsulant compositions therefrom as a forced stream of dry powder. Also provided are methods for treating spills, including biologic and acidic spills, using the above-described encapsulant compositions .

In yet another inventive aspect, it has been discovered that a highly effective device for treating aqueous spills is provided by a pressurized canister containing a free-flowing powder encapsulant composition including powder form superabsorbent polymer, which can dispense the powdered encapsulant composition from the canister under pressure. In particular, the powder form encapsulant composition is at least 70% by weight comprised of particles having a particle diameter of less than 500 microns, the encapsulant composition including at least one powder form superabsorbent polymer and preferably a mixture of at least two powder form superabsorbent polymers . Such devices are effective to broadcast the encapsulant composition rapidly and evenly over the spill, so as to achieve absorption and encapsulation of the aqueous substance. Still further, the fine powder form of these preferred encapsulant compositions facilitates the formation of a solid, unitary mass upon absorption of the aqueous liquid, so as to expedite cleanup of the spill. Desirable superabsorbent polymers in this embodiment include acrylic and acrylamide polymers. In another feature of the invention, the use of argon gas to pressurize the canisters of encapsulant- containing devices as described above has been found to be particularly advantageous.

One object of the present invention is to provide improved compositions for encapsulating hazardous liquid substances.

Another object of the present invention is to provide improved methods for encapsulating hazardous liquid substances.

Additional objects, features and advantages of the present invention will be apparent from the descriptions herein.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a device for treating a spill of an aqueous liquid in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

For the purpose of promoting an understanding of the principles of the invention, reference will now be made to certain preferred embodiments thereof and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations, further modifications and applications of the principles of the invention as described herein being contemplated as would normally occur to one skilled in the art to which the invention relates .

As disclosed above, the present invention provides compositions, methods, and devices for treating hazardous spills. The invention provides and utilizes free-flowing encapsulant compositions which incorporate at least one particulate absorbent.

The absorbent in accordance with the present invention is most advantageously a particulate (e.g. granular or powdered) superabsorbent polymer. Such polymers are substantially water-insoluble, but water swellable polymers, which form hydrogels upon contacting aqueous liquids. A variety of superabsorbent polymer types are known and are suitable for use in the present invention. These hydrogel- forming absorbent polymers will typically have anionic functional groups such as sulfonic acid and/or carboxy groups .

Illustrative polymers suitable for use in the invention include those which are prepared from polymerizable, unsaturated, acid-containing monomers. Such monomers include the olefinically unsaturated acids and anhydrides that contain at least one carbon to carbon olefinic double bond. These monomers can be selected, for example, from olefinically unsaturated carboxylic acids and acid anhydrides, olefinically unsaturated sulfonic acids, and mixtures thereof.

Non-acid monomers may also be included, usually in minor amounts, in preparing the hydrogel-forming absorbent polymers herein. Such non-acid monomers can include, for example, the water-soluble or water- dispersible esters of the acid-containing monomers, as well as monomers that contain no carboxylic or sulfonic acid groups. Optional non-acid monomers can thus include monomers containing functional groups selected from carboxylic acid or sulfonic acid esters, hydroxyl groups, amide groups, amino groups, nitrile groups and quaternary ammonium salt groups. These non-acid monomers are well-known materials. For additional information as to such monomers, reference can be made for example to U.S. Pat. Nos. 4,076,663, and 4,062,817. Olefinically unsaturated carboxylic acid and carboxylic acid anhydride monomers include the acrylic acids typified by acrylic acid itself, methacrylic acid, ethacrylic acid, β-chloroacrylic acid, α- cyanoacrylic acid, β-methylacrylic acid (crotonic acid) , sorbic acid, angelic acid, cinnamic acid, p- chlorocinnamic acid, itaconic acid, citroconic acid, esaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid, tricarboxyethylene, maleic acid anhydride, and the like. Olefinically unsaturated sulfonic acid monomers include aliphatic or aromatic vinyl sulfonic acids such as vinylsulfonic acid, allyl sulfonic acid, vinyl toluene sulfonic acid and styrene sulfonic acid; acrylic and mothacrylic sulfonic acid such as sulfoethyl acrylate, sulfoethyl methacrylate, sulfopropyl acrylate, sulfopropyl methacrylate, 2- hydroxy-3-methacryloxypropyl sulfonic acid and 2- acrylamide-2-methylpropane sulfonic acid.

Preferred hydrogel-forming absorbent polymers for use in the present invention contain carboxy and/or carboxamide groups . These polymers include hydrolyzed starch-acrylonitrile graft copolymers, partially neutralized starch-acrylonitrile graft copolymers, starch-acrylic acid graft copolymers, partially neutralized starch-acrylic acid graft copolymers, saponified vinyl acetate-acrylic ester copolymers, hydrolyzed acrylonitrile or acrylamide copolymers, slightly network crosslinked polymers of any of the foregoing copolymers, partially neutralized polyacrylic acid, and slightly network crosslinked polymers of partially neutralized polyacrylic acid. Examples of these polymer materials are disclosed in U.S. Pat. Nos. 3,661,875, 4,076,663, 4,093,776, 4,666,983, and 4,734,478.

One preferred polymer class for use herein includes partially neutralized polyacrylic acids (e.g. poly (sodium acrylate/acrylic acid) polymers).

As described above, the hydrogel-forming absorbent polymers can be slightly network crosslinked. Network crosslinking serves to render the polymer substantially water-insoluble and, in part, determines the absorptive capacity and extractable polymer content characteristics of the precursor particles and the resultant macrostructures . In one feature of the present invention, it has been discovered that improved encapsulant compositions can be provided utilizing a blend of two superabsorbent polymers, wherein one of the polymers has an absorption time significantly greater than the other. In this regard, the absorption time for the superabsorbent, as that term is used herein, refers to the period of time required for the superabsorbent polymer to absorb 70% of its total capacity (by weight) for deionized water when immersed in deionized water. In preferred aspects of the invention, two superabsorbent polymers will be included in the encapsulant composition, wherein a first of the polymers has a first absorption time, and a second of the polymers has a second absorption time at least double (200% of) the first absorption time. Still further preferences exist wherein the second absorption time is at least about 500% that of the first, and/or wherein the first polymer has a absorption time of less than about 2 minutes . As examples, advantageous encapsulant compositions are provided wherein the first superabsorbant has an absorption time of less than about 1 minute, and the second superabsorbent polymer has an absorption time of greater than about 5 minutes , or even greater than about 10 minutes. Such mixtures provide compositions exhibiting controlled and effective absorption characteristics, more advantageous than those demonstrated by either superabsorbent polymer alone. Faster acting superabsorbents serve to control the spread of the spill while relatively slower acting superabsorbents assist in ensuring that a large portion or all of the spill is taken up by the encapsulant composition while forming a solid unitary mass upon final absorption of the spill. Using two such superabsorbents in combination also allows encapsulant formulations to be tailored for performance in absorbing specific types of spills.

More preferred encapsulant compositions include both polyacrylamide and polyacrylic (e.g. poly(Cι-C₆ alkyl) acrylic acid or esters thereof such as Ci-Cβ alkyl-poly (Cι-C₆ alkyl) acrylates ) superabsorbent polymers, and in one preferred form include at least two superabsorbent polyacrylamide polymers, and at least two superabsorbent polyacrylic polymers, wherein the polyacrylamide polymers have faster and slower absorption rates relative to each other as discussed above, and the polyacrylic polymers also have faster and slower absorption rates relative to each other as discussed above.

Preferred superabsorbent polymers will exhibit the capacity to absorb at least 20 times their own weight in deionized water, more preferably at least about 100 times their own weight in deionized water.

It has also been discovered that particle size of the superabsorbent polymer is highly important to the function of the encapsulant composition, particularly in providing free-flowing compositions which can be spray-applied and which form solid, unitary patties after contacting the aqueous spill. Thus, superabsorbent polymer powders, desirably wherein at least 70% of the particles have a particle diameter less than about 500 microns, are employed with preference. It is further preferred that 80% or more of the superabsorbent polymer particles have a particle diameter less than 500 microns. In this regard, particle size for such powders, as referred to herein, is determined by sieve size analysis. Thus, for example, a hydrogel-forming absorbent polymer particle that is retained on a standard #35 sieve with 500 micron openings is considered to have a particle size greater than 500 microns, and a hydrogel-forming absorbent polymer particle that passes through the #35 sieve with 500 micron openings is considered to have a particle size less than 500 microns.

Such differing superabsorbent polymers can be incorporated in any suitable weight ratio relative to one another. Generally, each superabsorbent polymer type will comprise at least 1% by weight of the total amount of superabsorbent polymer in the composition, more typically at least about 5% by weight, and most preferably at least about 10% by weight.

In one inventive embodiment, the encapsulant composition also includes an agent for forming an interpenetrating network between and among the absorbent particles. Such an agent can include multiple substances. For example, it can include a crosslinkable agent along with a crosslinking agent effective to crosslink the crosslinkable agent. These agents, when in the dry state, do not react significantly with one another. However, upon contacting the aqueous spill, these agents are taken up in the spill by dissolution, suspension or otherwise, and react with one another to form the interpenetrating polymer network between the absorbent particles. This network is preferably also a polymer hydrogel, and serves to bind the absorbent particles to one another and thereby form a unitary mass that can be removed from the spill site. While the present invention is not intended to be bound by any theory, it is believed that the interpenetrating hydrogel is beneficially dehydrated by the action of the particulate absorbent, leading to increased firmness of the interpenetrating gel and convenience in handling the absorbed mass. In addition, such an interpenetrating network can advantageously serve to entrain any other solids that may have been present in the spill, for example stomach contents in the case of vomit, or cells or tissues in the case of other biological fluids such as blood.

Preferred crosslinkable agents include polyols such as polyvinyl alcohols, and polysaccharides bearing free hydroxyl groups, such as gums, e.g. guar gum, xantham gum, and the like. Water soluble silicates, such as water soluble sodium silicates, may also be used. Such crosslinkable agents will typically be included in an amount of about 0.1% to about 20% of the encapsulant composition by weight, more preferably about 0.1% to about 10%.

Preferred crosslinking agents include those agents exhibiting the capacity to crosslink polyols to form an interpenetrating network between the absorbent particles. Most preferably, the encapsulant compositions includes a boron-containing compound such as borate, boric acid, or a mixture thereof, to effect crosslinking of the polyol. Such crosslinking agents will typically be included in an amount of about 0.1% to about 20% of the encapsulant composition by weight, more preferably about 0.1% to about 10%. In addition to their roles as crosslinkers , boric acid and borax are known disinfectants and antifungals, and borax is a known deodorant compound. These materials may serve beneficially in these capacities as well.

Preferred encapsulant compositions of the invention also include a flow agent which acts to inhibit adherence among particles of the superabsorbent polymer in the dry state, and thereby increase the overall flowability of the composition. This flow agent will typically be incorporated at a level of about 0.1% to about 10% by weight relative to the weight of the superabsorbent polymer (s) in the composition, more typically about 0.5% to about 5%. Such flow agents can be solids, for example as in the case of silica, or suitable fluid lubricants. It will also be understood that the composition may include other additives conventional to encapsulant compositions. For example, these may include surfactants, other absorbent particulates , and the like. In use, the encapsulant compositions of the invention are applied to an aqueous liquid spill, whereupon they absorb and encapsulate the liquid and advantageously form a unitary solid mass which can then be removed from the spill area. In this regard, the unitary solid mass in accordance with the invention may for instance appear as a continuous mass to the naked eye, or may appear as an agglomerated mass of particles. In any event, it is desired that this solid unitary mass form, as opposed to a fluid mass or individual particles .

Application of the encapsulant composition to the spill may be achieved by any suitable means . For example, the composition can be sprinkled or sprayed onto the spill. In its most preferred form, the encapsulant composition has flow properties rendering it a sprayable mass so as to evenly distribute the mass upon the spill. Further, upon application to the spill, the encapsulant composition will swell as it absorbs the liquid, whereupon the composition stably incorporates the liquid and will not release the same under normal handling conditions. The time necessary for encapsulation of the spill will of course vary based upon the particular encapsulant composition used and the substance to be encapsulated. Typically, the encapsulation will occur within a span of about 1 to 60 minutes. In that period, the preferred compositions form a unitary, solid mass which can be taken up from the spill site.

As to types of spills which can be treated in accordance with the invention, they may be solid surface- or liquid-bound spills. A wide variety of liquids are treatable in accordance with the invention. These include for example aqueous liquids such as biological fluids, for instance vomit, urine, blood, and the like, as well as other chemical hazards such as acidic or caustic spills. Acidic spills can include, for example, spills of aqueous acids, especially strong acids such as hydrochloric, hydrobromic, sulfuric or nitric acid. In the case of such strong acids, it has been found that a unitary solid mass is formed upon applying a powder form superabsorbent encapsulant composition, even where such composition is free from a separate agent for forming an interpenetrating polymer network as described above . In another aspect of the invention, a device is provided for containing and dispensing encapsulant compositions. With reference now to FIG. 1, the apparatus 10 includes a pressurized canister 11 equipped to dispense a powder under pressure. A free flowing encapsulant composition 12 is contained in the vessel. The canister includes, for example, a nozzle 13 and a trigger 14 as is conventional for such equipment. The pressure within the canister 11 is typically about 50 to about 250 psi, and the canister is pressurized using a suitable gas, for example air or an inert gas such as nitrogen or argon. In one feature of the invention, it has been discovered that pressurization with argon gas provides a particularly advantageous device, more readily and uniformly dispensing the powder compositions from the pressure vessel even under relatively lower pressure conditions, for example about 150 psi or lower, e.g. in the range of about 50 psi to about 150 psi. For the purpose of promoting a further understanding of the invention and its advantages, the following specific examples are provided. It will be understood that these examples are illustrative and not limiting of the invention.

EXAMPLE 1

An encapsulant composition of the invention was prepared by mixing the materials specified in Table 1. All materials except sodium hypochlorite were added as dry materials, and mixed for about 1 minute at high speed using an electric mixer equipped with an angled wide-blade turbine. While mixing at high speed, the hypochlorite solution was slowly added to the dry components and mixed for about 5 minutes more. After two days at room temperature, drying was completed in a 90°C oven for 15 hours. The sample was then placed in a capped glass bottle.

TABLE 1

^aA E Staley Manufacturing Company, Decatur, Illinois. ^bAιr Products and Chemicals, Inc , Knoxville, Tennessee ^cAqualon Division, Hercules Incorporated, Wilmington, Deleware ^dStockhausen, Inc , Greensboro, North Carolina ^eJRM Chemical, Inc , Cleveland, Ohio ^fD J Enterprises, Cleveland, Ohio

EXAMPLE 2

The encapsulant composition prepared in Example 1 was tested in the following fashion. A known mass of a 40% water / 60% ethylene glycol solution was added to a wide mouth glass dish. A known mass of the encapsulant composition was then added to the surface of the solution. Sufficient absorbent was added to absorb all of the test liquid. The encapsulant to test liquid mass ratio was then calculated, and found to be 1:9. In addition, it was observed that the encapsulant composition formed a solid, relatively firm patty.

EXAMPLE 3

Another encapsulant composition of the invention was prepared by mixing the materials specified in Table 2. The materials were mixed for about 5 minutes at using an electric mixer as described in Example 1. The sample was then placed in a capped glass bottle.

TABLE 2

^aStockhausen, Inc., Greensboro, North Carolina. ^bJRM Chemical, Inc., Cleveland, Ohio.

EXAMPLE 4

The encapsulant composition prepared in Example 3 was tested in a fashion similar to that described in Example 2, except the test liquid was 36% aqueous hydrochloric acid. A relatively firm patty was formed. The encapsulant to test liquid weight ratio was about 1:2.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.

All publications cited herein are indicative of the level of skill in the art and are hereby incorporated by reference as if each had been individually incorporated by reference and fully set forth.

Claims

WHAT IS CLAIMED IS:

1. An encapsulant composition for treating a hazardous liquid spill, comprising: at least one particulate absorbent for absorbing the liquid; and a polymer matrix forming agent for forming an interpenetrating polymer network between particles of said absorbent upon contacting the liquid, wherein the encapsulant composition forms a solid unitary mass upon absorbing the liquid.

2. The encapsulant composition of claim 1, for treating an aqueous spill, wherein said particulate absorbent includes at least one particulate superabsorbent polymer, and wherein said polymer matrix forming agent comprises a water soluble crosslinkable agent and a water soluble crosslinking agent for crosslinking said crosslinkable agent to form said polymer network.

3. The encapsulant composition of claim 2, wherein said crosslinkable agent is a polyol.

4. The encapsulant composition of claim 3, wherein said polyol is polyvinyl alcohol.

5. The encapsulant composition of claim 2, wherein said crosslinkable agent is a polysaccharide.

6. The encapsulant composition of claim 5, wherein said polysaccharide is guar gum.

7. The encapsulant composition of claim 1, wherein said particulate absorbent includes at least one superabsorbent polymer.

8. The encapsulant composition of claim 7, wherein said particulate absorbent includes two or more superabsorbent polymers.

9. The encapsulant composition of claim 8, wherein said particulate absorbent includes a first superabsorbent polymer having a first absorption time, and a second superabsorbent polymer having a second absorption time, said second absorption time being at least 200% of said first absorption time.

10. The encapsulant composition of claim 9, wherein said first and second superabsorbent polymers are polyacrylamide polymers .

11. The encapsulant composition of claim 8, wherein said particulate absorbent includes a polyacrylamide superabsorbent polymer and a polyacrylate superabsorbent polymer .

12. The encapsulant composition of claim 11, wherein said crosslinkable agent includes at least one polyol and said crosslinking agent includes boric acid, borax, or a combination thereof.

13. The encapsulant composition of claim 12, wherein said crosslinkable agent includes at least one polyol .

14. The encapsulant composition of claim 13, wherein said at least one polyol includes polyvinyl alcohol and guar gum.

15. An encapsulant composition for treating an aqueous acid spill, comprising: a first particulate superabsorbent polymer for absorbing aqueous fluids, said first superabsorbant polymer having a first absorption time; and a second particulate superabsorbent polymer for absorbing aqueous fluids, said second superabsorbent polymer having a second absorption time, said second absorption time being at least about 200% of said first absorption time.

16. The encapsulant composition of claim 15, wherein said first and second superabsorbent polymers are polyacrylamide polymers .

17. The encapsulant composition of claim 15, wherein said first superabsorbent polymer has an absorption time such that it absorbs 70% of its capacity in less that about one minute.

18. The encapsulant composition of claim 17, wherein said second superabsorbent polymer has a water absorption rate such that it absorbs 70% of its capacity in more than about five minutes.

19. The encapsulant composition of claim 18, wherein said first and second superabsorbent polymers are polyacrylamide polymers .

20. The encapsulant composition of claim 19, also including at least a third particulate superabsorbent polymer, said third superabsorbent polymer being a polyacrylate polymer.

21. The encapsulant composition of claim 20, including a third and a fourth particulate superabsorbent polymer, said third and fourth particulate polymers being polyacrylate polymers.

22. The encapsulant composition of claim 21, wherein said third particulate superabsorbent polymer has a higher level of surface crosslinking than said fourth particulate superabsorbent polymer.

23. A device for treating a spill of a liquid, comprising : a pressurized canister; encapsulant composition contained in said canister, the encapsulant composition including at least one particulate absorbent for absorbing the liquid, and a polymer matrix forming agent for forming an interpenetrating polymer network between particles of said absorbent upon contacting the liquid, wherein the encapsulant composition forms a solid unitary mass upon contacting the liquid; and wherein the pressurized canister is operable to dispense said particulate encapsulant composition under pressure .

24. The device of claim 23, for treating a spill of an aqueous liquid, wherein said polymer matrix forming agent comprises a water soluble crosslinkable agent and a water soluble crosslinking agent for crosslinking said crosslinkable agent to form said polymer network.

25. The device of claim 24, wherein said crosslinkable agent is a polyol.

26. The device of claim 23, wherein said particulate absorbent includes at least one superabsorbent polymer.

27. The device of claim 26, wherein said particulate absorbent includes two or more superabsorbent polymers .

28. The device of claim 27, wherein said particulate absorbent includes a first superabsorbent polymer having a first absorption time, and a second superabsorbent polymer having a second water absorption time, said second absorption time being at least 200% of said first absorption time.

29. A device for treating a spill of a liquid, comprising : a pressurized canister; an encapsulant composition contained in said canister, the encapsulant composition including: a first particulate superabsorbent polymer for absorbing the liquid, said first superabsorbant polymer having a first absorption time; and a second particulate superabsorbent polymer for absorbing the liquid, said second superabsorbent polymer having a second absorption time, said second absorption time being at least about 200% of said first absorption time; and wherein the pressurized canister is operable to dispense said particulate encapsulant composition under pressure .

30. The device of claim 29, wherein said first and second superabsorbent polymers are polyacrylamide polymers .

31. The device of claim 29, wherein said first superabsorbent polymer has an absorption time of less than about one minute .

32. The device of claim 31, wherein said second superabsorbent polymer has an absorption time of more than about five minutes .

33. The device of claim 32, also including at least a third particulate superabsorbent polymer, said third superabsorbent polymer being a polyacrylic polymer .

34. The device of claim 33, including a third and a fourth particulate superabsorbent polymer, said third and fourth particulate polymers being polyacrylic polymers .

35. A method for treating a liquid spill, comprising: applying to the liquid spill a particulate encapsulant composition including absorbent particles for absorbing the liquid; and forming an interpenetrating polymer network between said absorbent particles after said applying, wherein said particulate encapsulant composition forms a unitary mass after contacting said liquid spill.

36. The method of claim 35, wherein said liquid is an aqueous liquid, and wherein said particulate encapsulant composition includes a polymer matrix forming composition for forming the interpenetrating polymer network between particles of said absorbent upon contacting the aqueous spill, the polymer matrix forming composition including a water soluble crosslinkable agent and a water soluble crosslinking agent for crosslinking said crosslinkable agent to form said polymer matrix.

37. The method of claim 36, wherein said crosslinkable agent is a polyol.

38. The method of claim 37, wherein said particulate absorbent includes at least one superabsorbent polymer .

39. The method of claim 38, wherein said particulate absorbent includes two or more superabsorbent polymers .

40. A method for treating a liquid spill, comprising: applying to the liquid spill a particulate encapsulant composition including: a first particulate superabsorbent polymer for absorbing the liquid, said first superabsorbant polymer having a first absorption time; and a second particulate superabsorbent polymer for absorbing the liquid, said second superabsorbent polymer having a second absorption time, said second absorption time being at least about 200% of said first absorption time; and allowing said encapsulant composition to absorb said liquid.

41. The method of claim 40, wherein said spill is an aqueous spill.

42. The method of claim 41, wherein said aqueous spill is an aqueous strong acid.

43. The method of claim 42, wherein said acid is selected from hydrochloric acid, hydrobromic acid, sulfuric acid and nitric acid.

44. A device for treating a liquid spill, comprising : a pressurized canister; a particulate encapsulant composition contained in said pressurized canister, said particulate encapsulant composition comprising a powder form superabsorbent polymer, wherein at least 70% by weight of the superabsorbent polymer particles have a particle diameter of less than 500 microns; and wherein the pressurized canister is operable to dispense said particulate encapsulant composition as a forced stream.

45. The device of claim 44, wherein said encapsulant composition also includes a flow agent.

46. The device of claim 45, wherein said flow agent includes silica.

47. The device of claim 45, wherein said encapsulant composition also includes a chlorine source.

48. The device of claim 47, wherein said chlorine source includes hypochlorite.

49. The device of claim 48, wherein said particulate encapsulant composition also comprises starch.

50. The device of claim 48, wherein said particulate encapsulant composition also comprises a crosslinkable polyol, and a crosslinking agent for crosslinking the polyol upon contacting the aqueous spill.