FIELD OF THE INVENTION: The present invention relates to novel methods for adsorbing nonpoiar and weakly polar molecules from liquids and gases which involve contacting the liquid or gas with an effective amount of a deaiuminated, nonderivatized zeolite. For example, nonpoiar and weakly polar molecules such as benzene, xylene, toluene and ammonia can readily be removed from water. The deaiuminated zeolite can be incorporated into an absorbent material, filter or even a surface material for ease of convenience. For example, the deaiuminated zeolite can be incorporated into diapers, clothing, surgical masks, bedsheets, bedpads, blankets, animal litter, diaper pails, filters, filtering aides, wall coverings, countertops, cutting boards, and the like. BACKGROUND OF THE INVENTION: Zeolites include crystalline, hydrated alkali- aluminum silicates of the general formula:

M _2/n O- (A1 ₂ 0 ₃ ) ^• [y(Si0 ₂ ) ] -wH ₂ 0 wherein is a cation of valence n, w is the number of water molecules, and y is 2 or more. The cation is mobile and can undergo ion exchange. See U.S. Patent

2,882,243 to Milton. Zeolites occur naturally in volcanic rocks, altered basalts, ores and clay deposits but can also be chemically synthesized.

Zeolites have been used as catalysts, adsorbents and ion exchange media in chemical and hydrocarbon processing procedures. Some forms of crystalline aluminosilicate zeolites can be regenerated after use in such procedures, often by acid treatment or thermal treatment at very high temperatures . Resistance to such treatment is related to the presence of a higher proportion of Si0 ₂ relative to A1 ₂ 0 ₃ in the aluminosilicate. See U.S. Patent 3,691,099 to Young.

Crystalline, hydrated aluminous tectosilicates of Group I and II elements such as potassium, magnesium and

calcium are also formed in nature or may be synthesized in the laboratory. Higher polyvalent ions, such as the rare earths, are readily introduced by cation exchange. Structurally, these tectosilicates form an aluminous silicate "framework" extending as an infinite three- dimensional network of A10 ₄ and Si0 ₄ tetrahedra linked together by shared oxygen atoms. These aluminous tectosilicates are represented by the empirical unit cell formula: M _χ/n [(Al0 ₂ ) _χ (Si0 ₂ ) _y ]wH ₂ 0 wherein M is a cation of valence n, w is the number of water molecules, x is the number of A10 ₂ units and y is the number of Si0 ₂ units. The ratio of y/x is usually about 1 to about 10. The sum of x and y is the total number of tetrahedra in the unit cell.

Channels and pores uniformly penetrate the entire volume of the solid zeolite. When water is removed from these zeolites, large internal surface areas become available to adsorb liquids or gases. Thus, the external surface area of a zeolite represents only a small portion of its total available surface area. Moreover, the dehydrated zeolite selectively adsorb or reject different molecules on the basis of their effective molecular sizes and shapes. Point electric charges on the surfaces of aluminous zeolite pores adsorb highly polar molecules such as water, alcohols and the like. Such hydrophilicity has been exploited to remove water from polar substances which are less readily adsorbed by the aluminous zeolite, for example, hydrocarbons processed by the petroleum industry. Gas streams may also be dried with a dehydrated zeolite due to its extremely strong attraction for water. Zeolites have been used to remove carbon monoxide from tobacco smoke while permitting larger, flavor-imparting molecules to remain in the smoke. Both naturally-occurring and synthetically-prepared zeolites have also been used to remove nitrogenous components from

liquid human and animal wastes by ion exchange. See U.S. Patent No. 3,935,363 to Burholder. Metal catalysts have been introduced into zeolites for converting carbon monoxide to carbon dioxide or for catalyzing the hydrogenation and cracking of petroleum feedstocks. See British Patent No. 2,013,476A. Hydrophobic tectosilicates, developed to resist water absorption, will adsorb less polar substances from mixtures containing water. See U.S. Patent Nos. 4,744,374 and 4,683,318. For example, U.S. Patent No. 3,682,996 to

Kerr disclosed silylation of free hydroxy sites in zeolites by trimethylsilan (H-Si(CH ₃ ) ₃ ) and that such silylated zeolites adsorbed about 40% less cyclohexane, n-hexane and water than the parent "hydrogen" zeolites of type II. U.S. Patent 4,744,374 to Deffeyes et al . , provides deaiuminated zeolites which have been derivatized with substituents that have a weaker point electric source than aluminum.

However, there has been no recognition that simple removal of aluminum from an aluminous zeolite will make that zeolite sufficiently hydrophobic to adsorb and remove nonpoiar and weakly polar molecules from more polar liquids and gases. Surprisingly, while the skilled artisan would expect dealumination to expose hydroxyl groups, producing a deaiuminated zeolite that would more readily adsorb polar molecules than nonpoiar molecules, the present deaiuminated zeolites adsorb nonpoiar and weakly polar molecules even in the presence of polar molecules like water. According to the present invention, deaiuminated zeolites which have not been derivatized with any nonpoiar molecule are excellent adsorbents of nonpoiar and weakly polar molecules such as benzene, xylene, toluene and ammonia. The present invention provides compositions and methods of using deaiuminated zeolites for adsorbing nonpoiar and weakly polar molecules even when water is present .

According to the present invention, deaiuminated, nonderivatized zeolites are readily and inexpensively manufactured without the side products often produced by derivatization conditions. The simple, inexpensive manufacture of these materials makes them ideal for incorporation into disposable units such as filters and diapers .

The present deaiuminated zeolites have particular utility in disposable diapers. Urine and feces contain metabolic breakdown products and ammonia that can cause dermatological problems . These dermatological problems can also be exacerbated by ammonia formed by the breakdown of urea. The skin is irritated by ammonia at concentrations of 10,000 ppm. Exposure to 20,000 to 30,000 ppm of ammonia can produce burns and blistering.

See Proctor et al . , Chemical Hazards of the Workplace (2d ed. 1988) ; 2B Patty's Industrial Hygiene and Toxicology 3045 (1981) . Moreover, ammonia gas can be life- threatening to healthy adults at levels of about 1000 parts per million(ppm) . The safe industrial limit of exposure to ammonia by adults is 50 ppm. Breathing 5000 ppm can be immediately fatal .

Infants and the elderly can be even more sensitive to dermatological problems and to the effects of ammonia. For example, low birth weight infants often have underdeveloped respiratory systems which may be especially vulnerable to the toxic effects of ammonia. Infants and the elderly with any form of pulmonary disfunction such as bronchopul onary dysplasia, chronic respiratory failure and pulmonary hypertension may succumb to ammonia poisoning more easily than healthy individua

For example, a baby urinates about 0.75 ml to 1.0 ml of urine per hour per kilogram of bodyweight . Urine is about 96% water, 2% urea and 2% other materials. The excreted urine passes through a membrane-sleeve of conventional disposable diapers, which are highly effective at absorbing water but not very effective at

absorbing ammonia or ammonium ions. Moreover, while water is held tightly, a conventional diaper does not prevent microbial growth. In the presence of such microbes, urea present from excreted urine and feces begins to break down in minutes into ammonia and ammonium, by the following formulae:

C0(NH ₂ ) ₂ + H ₂ 0 > C0 ₂ + 2 NH ₃

CO(NH ₂ ) ₂ + 2 H ₂ 0 > HC0 ₃ ^" + NH ₄ ⁺ + NH ₃

The rate of in vitro ammoniation increases hourly by 5.8%, 6.3%, 8.0% and 9.7% through hours 2 to 5 after voiding. This steeply increasing rate of ammoniation is caused by growing colonies of bacteria and the consequent accumulation of urease which deaminates urea.

The pH of urine at the time of voiding is about 6.0, but, as NH ₄ 0H and NH ₃ continually form over time the pH rises. At about three hours the pH is about 9.0 and NH ₃ gas flows continuously. While microbial growth is somewhat slowed by pH 6.0 urine, an increased pH stimulates bacterial growth. Each urination provides fresh urea to start a new cycle of deamination. Ammonia is also formed by breakdown of microbial amino acids. This rising pH provides an increasingly hospitable environment for bacterial and other microbial colonies. Moreover, even though the growth of microbes is momentarily slowed by a fresh voiding of pH 6.0 urine, such microbes quickly recover, continue growing and decompose more urea and amino acids.

Once ammonia gas is formed, it begins escaping back across a conventional diaper's membrane-sleeve where it contacts the skin and feces, if present. Ammonia elevates the pH of whatever medium it contacts. For example, the alkaline ammonia gas elevates the fecal pH which activates proteolytic enzymes that vigorously metabolize skin, causing irritations, rashes or lesions. Such damage makes the skin more vulnerable, not only to ammonia, but to opportunistic microbes, including fungi

such as Candida, and bacteria that normally do not inhabit the skin.

Skin rashes and irritations are frequently treated with salves and ointments. For example, U.S. Patent 4,556,560 to Buckingham provides a lipase-inhibiting agent which is preferably applied with a barrier-like vehicle for treatment of diaper rash and diaper dermatitis. Medicated greases such as Balmex ^® and A&D Ointment ^® are also widely available. However, while these products may provide some protection from ammonia burns, they also block oxidation of the injured skin and create an ideal environment for growth of anaerobic bacteria. Therefore, a long-standing need exists for a new solution to dermatological problems such as diaper rash and dermatitis.

According to the present invention, deaiuminated zeolites can adsorb nonpoiar and weakly polar molecules such as benzene, xylene, toluene and ammonia and have particular utility for preventing diaper rash and dermatitis.

SUMMARY OF THE INVENTION:

The present invention provides compositions and methods for adsorbing or removing nonpoiar and weakly polar molecules from polar liquids and gases.

In one embodiment, the present invention is directed to a composition including an effective amount of dealuminized zeolite in a carrier. Such a composition can be dry or liquid. When dry, the composition can be incorporated into a diaper, clothing, bedsheet, bedpad, blanket, filter, filtering aide, wall covering, countertop, cutting board, and the like. The present compositions can also be used in a liquid suspension to adsorb and remove nonpoiar and weakly polar molecules such as benzene, xylene, toluene, ammonia and the like from more polar liquids such as water.

In another embodiment, the present invention provides methods of adsorbing nonpoiar or weakly polar molecules which includes contacting the nonpoiar and weakly polar molecule with an effective amount of a dealuminized zeolite.

This and other objectives of the present invention are more specifically described in the detailed description of the invention, provided hereinbelow. BRIEF DESCRIPTIONS OF THE DRAWINGS: Fig. 1 depicts procedures for dealuminating aluminous tectosilicates. Starting materials are depicted by formula I :

(sSi-0) ₄ A1_M ⁺ I wherein M ⁺ is a metal cation. These starting materials are treated with acid to provide aluminum-associated hydroxyl sites on the tectosilicate of formula II:

(=Si-0) ₃ Al + HO-Si= II

These deaiuminated tectosilicates contain tetracoordinated hydroxylated nests of about four __Si-OH moieties. Heating at low temperatures of about 100°C to 200°C clears pores and channels in the tectosilicates by removing water of hydration.

Fig. 2 provides a bar graph depicting the parts per million of xylene remaining in water treated with deaiuminated clinoptilolite as compared to zeolite derivatized with methylsilane (ZeoLog CH ₃ Si) , methanol {ZeoLog CH ₃ OH) and dichlorodimethylsilane (DCDMS Zeolog) . As illustrated, water treated with deaiuminated clinoptilolite has less residual xylene than water treated with any of the derivatized zeolites.

Fig. 3 provides a bar graph depicting the parts per million of toluene remaining in water treated with deaiuminated clinoptilolite as compared to zeolite derivatized with methylsilane (ZeoLog CH ₃ Si) , methanol (ZeoLog CH ₃ OH) and dichlorodimethylsilane (DCDMS Zeolog) .

As illustrated, water treated with deaiuminated clinoptilolite has as little residual toluene as water

treated with the methylsilane and methanol derivatized zeolites. Also, as illustrated, water treated with deaiuminated clinoptilolite has even less residual toluene than water treated with the dichlorodimethylsilane derivatized zeolite.

Fig. 4 provides a bar graph depicting the parts per million of benzene remaining in water treated with deaiuminated clinoptilolite as compared to zeolite derivatized with methylsilane (ZeoLog CH ₃ Si) , methanol (ZeoLog CH ₃ OH) and dichlorodimethylsilane (DCDMS Zeolog) .

As illustrated, water treated with deaiuminated clinoptilolite has less residual benzene than water treated with the dichlorodimethylsilane and methanol derivatized zeolites. Also, as illustrated, water treated with deaiuminated clinoptilolite has much less residual benzene than water treated with one of the best- known benzene-adsorbents which is currently in use, FS- 300 Carbon.

DETAILED DESCRIPTION OF THE INVENTION:

According to the present invention, deaiuminated zeolites adsorb and remove nonpoiar and weakly polar molecules from more polar liquids and gases. In one embodiment, the present invention provides compositions which include an effective amount of a deaiuminated zeolite in a carrier. In another embodiment, the present invention provides a method of removing a nonpoiar molecule from a polar liquid or gas which includes contacting the nonpoiar or weakly polar molecule with an effective amount of a deaiuminated zeolite.

Polar liquids and gases from which such nonpoiar and weakly molecules can be removed include, water, urine, smoke, landfill leachate, air and the like.

Molecules which can be adsorbed by the present deaiuminated zeolites include any nonpoiar or weakly polar molecule which is small enough to enter the deaiuminated zeolite's pores. In general, such nonpoiar

or weakly polar molecules are smaller than about 12 Angstroms. Such nonpoiar and weakly polar molecules are less polar than water and include hydrocarbons, alcohols, amines, mercaptans and the like. In a preferred embodiment, the compositions and methods of the present invention are used to adsorb benzene, xylene, toluene, ammonia and the like.

Both naturally-occurring and synthetic zeolites are used in the compositions and methods of the present invention. Deaiuminated zeolites have interior acid sites provided by protons which are left when the aluminum is removed. These interior acid sites react with, and hold cations as well as nonpoiar and weakly polar molecules such as ammonia. Because the interior acid sites are inside the zeolite materials, these acid sites do not touch the skin.

Synthetic zeolites for use in the present compositions and methods include deaiuminated zeolites such as ZeoPhob™, ZeoLog™, ZeoLogCN-METHANOL™, Zeolite A (see U.S. Patent 2,882,243) ; Zeolite B (see U.S. Patent 3,008,803) ; Zeolite D (see Canada Patent No. 611,981) ; Zeolite E (see Canada Patent No. 636,931; Zeolite F (see U.S. Patent No. 2,995,358) ; Zeolite H (see U.S. Patent No. 3,010,789); Zeolite J (see U.S. Patent 3,011,869); Zeolite KG (see U.S. Patent 3,056,654); Zeolite L (see Belgium Patent No. 575,117); Zeolite M (see U.S. Patent 2,995,423); Zeolite 0 (see U.S. Patent 3,140,252); Zeolite Q (see U.S. Patent No. 2,991,151) ; Zeolite R (see U.S. Patent 3,030,181) ; Zeolite S (see U.S. Patent 3,054,657) ; Zeolite T (see U.S. Patent 2,950,952) ;

Zeolite W (see U.S. Patent 3,012,853) ; Zeolite X (see U.S. Patent No. 2,882,244) ; Zeolite Y (see U.S. Patent 3,130,007) ; and Zeolite Z (see Canada Patent No. 614,995) . Naturally-occurring aluminosilicate zeolites which are used in the present compositions and methods include analcite, brewsterite, chabazite, clinoptilolite,

dachiardite, datolite, erionite, faujasite, ferrierite, flakite, gmelinite, harmotone, heulandite, leucite, levynite, mesolite, mordenite, natrolite, noselite, paulingite, phillipsite, scolecite, stilbite, and yugawaralite . Naturally-occurring zeolites are preferred. A preferred naturally-occurring zeolite is clinoptilolite.

The hydrophobic zeolites of the present invention are prepared by removing a substantial proportion of the aluminum from the lattice sites of a tectosilicate, and dehydrating the resulting aluminum-deficient tectosilicate. According to the present invention, dealumination can be partial as well as complete. However, extreme dealumination has contributed to some loss of silicate lattice structure under some preparation conditions, for example, when the deaiuminated zeolite is heated to extreme temperatures during dehydration. Hence, dealumination preferably does not cause extensive loss of the zeolite lattice structure. Preferred deaiuminated zeolites have about 25% to about 100% of the aluminum removed and have an intact lattice structure.

Surprisingly, the deaiuminated zeolites of the present invention adsorb nonpoiar and weakly polar molecules better than they adsorb water -- the present deaiuminated zeolites actually prefer weakly polar and nonpoiar molecules over water. Hence, the present methods can be practiced even when liquid water or water vapor is present .

Preferably, the nonpoiar and weakly polar molecules which are bound by the present deaiuminated zeolites are smaller than about 12 Angstroms. Such nonpoiar molecules include hydrocarbons, alcohols, amines, mercaptans and the like.

Zeolites are deaiuminated so as to produce the requisite binding sites in the silicaceous lattice.

Preferably, dealumination is accomplished by treatment with aqueous mineral acid or nitric acid. The

deaiuminated tectosilicate is then dehydrated to expose lattice binding sites. Dealumination can be by known procedures, e.g. those provided in U.S. Patent Nos. 4,683,318 and 4,744,374 to Deffeyes, the disclosures of which are incorporated herein by reference.

A general reaction scheme for dealuminating tectosilicate zeolites is depicted in FIG. 1. Exposure of tectosilicates to aqueous acids replaces the metal cation (M+) of tectosilicates with a hydronium ion. As depicted in FIG. 1, a Si-O-Al bond of starting material I readily protonates and dissociates to provide aluminum- associated hydroxyl sites within the lattice as shown by structure II.

Aluminous tectosilicates having a silicon to aluminum ratio (Si:Al) of greater than about 5 are almost totally deaiuminated without loss of lattice integrity. See R. M. Barrer and M. B. Makki, 42 Can. J. Chem. 1481 (1964) . This is accomplished by extended treatment of aluminous tectosilicates with aqueous acid. Dealumination yields tectosilicates having tetracoordinated hydroxylated nests containing about 4 associated =Si-OH moieties (see Fig. structure IV) . These aluminum-free sites are termed "exoaluminum sites". Deaiuminated tectosilicate materials both of structure II and IV exhibit reduced hydrophilicity because of the absolute reduction of lattice charge from aluminum removal, and adsorb little water. Heating aluminum-containing or deaiuminated tectosilicates to relatively low temperatures, i.e., to about 100°-200°C, preferably in the presence of a vacuum, clears pores and channels by removing water of hydration from the pores. However, exposure of deaiuminated tectosilicates to higher temperatures, i.e., to about 400°-500°C, can cause destruction of the hydroxyl nests, via dehydroxylation and formation of new Si-O-Si bonds.

Dealuminized mordenites having Si:Al ratios of greater than 80 will not adsorb water vapor at a pressure of one

60 (1976) .

The aluminous tectosilicates utilized as starting materials for preparing derivatized tectosilicates can include crystalline, amorphous and mixed crystalline amorphous tectosilicates of natural or synthetic origin or mixtures thereof. The water insoluble crystalline tectosilicates useful in the present invention are those that possess interstitial channels of a diameter of about 3-13A. Hereinafter this diameter will be referred to as pore size.

A preferred pore size for the unmodified zeolite materials which is useful in this invention is about 3- 10A, most preferably 4-8A. The pore size of any given tectosilicate must be large enough to admit the nonpoiar or weakly polar molecule which is to be bound, i.e., hydrocarbons, alcohols, amines, mercaptans and the like. Tectosilicates possessing pore sizes with the range of about 4-13A readily admit small gaseous elements and compounds such as water (kinetic diameter [σ] 2.65A) , carbon monoxide (σ=3.76A) , carbon dioxide (σ-3.30A) and ammonia (σ=2.60A) .

The most useful aluminous tectosilicate starting materials preferably possess a lattice silicon to aluminum ratio of greater than about 5:1. Tectosilicates having a silicon to aluminum ratio of less than about five tend to lose their structural integrity upon dealumination.

An especially preferred class of aluminous tectosilicate starting materials is the naturally- occurring clinoptilolites . These minerals typically have the unit cell structure of the formula:

Na ₆ [ (Al0 ₂ ) _g (SiO ₂ ) ₃₀ ] 24H ₂ 0 wherein the sodium ion content (Na+) is partially replaced by calcium, potassium and/or magnesium, etc. The silicon:aluminum ratio in preferred varieties is greater than 5 and most preferably greater than about 8.

12

The pore size is in the range of about 4.0-6.0A. Clinoptilolite is stable in air to about 700°C and maintains its structural integrity upon dealumination. Other naturally-occurring aluminous tectosilicates that are useful as starting materials are the mordenites, which typically exhibit the unit cell composition:

Na ₈ [ (A10 ₂ ) ₈ (SiO ₂ ) ₄₀ ] .24H ₂ 0 wherein calcium and potassium cations can replace a part of the sodium cations. The pore size is in the range of about 3.5-4.5A. The silicon to aluminum ratio is generally greater than 5 but can be greater than 10. Other aluminous tectosilicates such as ferrierite or erionite also provide useful starting materials. Although naturally-occurring aluminous tectosilicates are the preferred starting materials due to their low cost and accessibility in large quantities, the synthetic analogs of the natural tectosilicates are of equivalent utility in the present method. For example, synthetic mordenite (Zeolon ^® ) , available from the Norton Company, is an acceptable starting material for providing dealuminized zeolites. Also, other synthetic, porous tectosilicates which have no equivalent in nature could serve as acceptable starting materials. The formation of the hydrophobic materials of the present invention normally proceeds by dealumination and then dehydration. The dealumination of aluminous tectosilicates with acid is well known in the art. For example, R. M. Barrer & M. B. Makki (42 Canadian J. Chem. 1481 (1964) ) reported the complete dealumination of clinoptilolite by refluxing samples in aqueous hydrochloric acid of varying concentration. In the present method, a strong acid treatment is preferred, involving exposing pulverized, sieved aluminous tectosilicate to refluxing, i.e. boiling 2-ION aqueous mineral acid for about 1-3 hours. Strong acids such as hydrochloric acid, sulfuric acid, nitric acid or phosphoric acid are preferably used. The more preferred

acid is hydrochloric acid, at concentrations of about 3N to about 7N.

In some cases, dealumination is accomplished by a mild acid treatment involving the percolation of aqueous acid through a column of crushed aluminous tectosilicate under ambient conditions. Preferably, the tectosilicate starting material is deaiuminated to achieve a Si:Al ratio of greater than about 25, but preferably the ratio exceeds 100, e.g. about 150-300. Under the most preferred conditions essentially no lattice aluminum is retained, as measured by X-ray fluorescence.

The deaiuminated, air-dried tectosilicate materials are then heated in order to remove most of the pore water of hydration and to expose the remaining lattice hydroxyl groups to derivatization. The heating is carried out at any temperature sufficient to effect substantial dehydration without causing significant lattice rearrangement and subsequent loss of reactive sites. Typically, the deaiuminated materials are heated to about 100°-200°C for about 10-40 hours, preferably under reduced pressure. Higher temperature treatment, for example, at about 500°-600°C, does not cause a further increase in hydrophobicity for tectosilicates that had been subjected to the acid treatment at ambient temperatures.

Following thermal dehydration at lower temperatures, e.g., about 100°-200°C, the majority of lattice silyl- hydroxyl groups which are present in tetracoordinated nests of the unit structure IV, as depicted in FIG. 1. These procedures readily afford hydrophobic microporous, crystalline silaceous materials which exhibit a greatly reduced affinity for water while maintaining high affinities for less polar molecules such as benzene, xylene, toluene and ammonia. The hydrophobicity or reduction in hydrophilicity of a tectosilicate is quantified in terms of its absorption of water per unit of tectosilicate under a given set of

exposure conditions (retention volume) . Water retention is measured in terms of ml H ₂ 0/g material at standard temperature and pressure. That any observed reduction in water retention is due to hydrophobicity as opposed to a general reduction in retention is established by measuring the retention of a similarly-sized molecule of comparable or lesser polarity, such as ammonia, nitrogen, methane or carbon dioxide. Microporous crystalline silaceous materials with reduced affinity for water vapor are useful in the methods of the present invention. Even wet deaiuminated tectosilicates effectively adsorb ammonia from human or animal excreta.

The present methods are practiced by incorporation of naturally-occurring zeolites and zeolites prepared as described hereinabove in diapers, bedpads, blankets, sheets, undergarments, outer clothing, surgical masks, surgical gowns, filters, filtering aides, wall coverings, countertops, cutting boards, and the like. Zeolites are incorporated into vapor-permeable compartments and moisture-permeable compartments, or distributed throughout the textile matrix.

Bedpads and disposable diapers typically consist of an adsorbent core of natural or synthetic fibers, a permeable top or inner sheet and a liquid-impervious back or outer sheet. While an effective amount of zeolite can be incorporated into any of these layers, the zeolite is preferably incorporated into the adsorbent core of the diaper or bedpad.

An effective amount of zeolite is incorporated into, or solution-coated onto, sheets, blankets, disposable diaper top sheets, plastic pants linings, cloth diapers, filters, filtering aides, wall coverings, countertops, cutting boards, and the like. Such methods of dispersing particulate solids onto and into fibrous substrates are known in the art.

The amount of zeolite used varies from about 1% to 50%, preferably about 15% to 25% of the weight of the

material. The amount used may depend on the particular use, for example, whether the material is intended for filtering materials which are highly contaminated with nonpoiar and weakly polar molecules or only slightly contaminated. In diapers, the amount used may depend on whether the diaper is to be worn during the day or night and whether the material is intended for use by an infant or an elderly person.

The methods of the present invention are also practiced with animals. For example, zeolites of the invention can be incorporated into animal litter, either alone or in combination with other adsorbent materials. Typical animal litter consists of adsorbent inorganic or organic materials such as attapulgite, vermiculite and calcium montmorillonite (i.e., clay) , agglomerated wood dust, wood chips, dehydrated grasses, straw, or alfalfa, fly ash and the like. The present zeolites are added in an effective amount, e.g. about 5-95%, preferably about 20% to 30% or more (based on total litter weight) to inhibit microbial growth and ammonia formation in the litter without substantially reducing the litter's adsorbent characteristics. For convenience, such litter preparations are aggregated into pellets.

The present deaiuminated zeolites are nontoxic and can even be fed to animals, e.g. to prevent ammonia build-up in poultry or animal bedding, litter and in swine wallows.

The new hydrophobic materials of this invention may also be used in filter cartridges in pipes, cigars or cigarettes, either alone or dispersed throughout and/or deposited on conventional tobacco smoke filtration materials. Used in this capacity, effective amounts of the new hydrophobic materials would be expected to adsorb significant amounts of carbon monoxide and carbon dioxide from the mainstream smoke more effectively than hydrophilic materials commonly used in smoke filters such as cellulose, activated carbon, naturally-occurring or

synthetic aluminous tectosilicates and the like. For example, a filter can be made having a section consisting of about 10-75 mg, preferably about 40 to 50 mg of the new hydrophobic material either front of or behind the standard filter material. Additionally, about 10-40 mg, preferably about 20 to 30 mg of the new material may be incorporated in the standard filter material itself. Likewise, effective amounts of the powdered materials of this invention could be incorporated into wrapping materials such as paper and tobacco leaf used to shape cigarettes or cigars in order to reduce the carbon monoxide in the sidestream smoke of the burning cigar or cigarette. The amount used will depend upon the total weight, volume and composition of the wrapping material used.

While certain representative embodiments of the invention have been described herein for purposes of illustration, it will be apparent to those skilled in the art that modifications therein may be made without departing from the spirit and scope of the invention.

The invention is further illustrated by reference to the following non-limiting examples.

Example 1

The following procedures were used to modify the properties of clinoptilolite (Hector, Cal . , NL Industries) .

PROCEDURE A _χ -- MILD ACID WASH

The tectosilicate, i.e., clinoptilolite, was crushed in a jaw crusher, then pulverized in a Braun Pulverizer. The pulverized material was passed through a 50-100 mesh RoTap ^® sieve agitator and used to fill 2-inch diameter, 3-foot long Pyrex ^® tube two-thirds full. The powdered material was held in place with a glass wool plug. Forty liters of hydrochloric acid (6N) are poured through the packed column at a rate of about 9 ml/min. at 27°C. The acid-treated material was washed by flushing with three column volumes of distilled water, then air-dried. Clinoptilolite (Hector, Cal.) treated in this manner is light green and exhibits a Si:Al ratio of approximately 30.

PROCEDURE A ₂ -- STRONG ACID WASH

The light green material 9225 g) isolated from procedure A ₁ was placed in a 4.0 liter round bottomed flask and 2.01 of 6N HCl was added. The slurry was heated at reflux for 2.0 hours. A white mineral was recovered by vacuum filtration and washed repeatedly with deionized water. The Si:Al ratio of clinoptilolite treated in this manner was about 212.

PROCEDURE -- MILD HEAT TREATMENT

About 10 g of pulverized tectosilicate (clinoptilolite) was placed in a 250 ml beaker and heated to 150°C for 20 hours in a vacuum drying oven at less than 10 mm Hg. After vacuum heating, the material was stored at 150°C at ambient pressure.

PROCEDURE H ₂ -- HIGH HEAT TREATMENT

About 10 g of pulverized tectosilicate (clinoptilolite) was placed in a quartz 250 ml beaker and heated at 550°C for 14 hours at ambient pressure, then transferred to a 150°C oven for storage at ambient pressure .

PROCEDURE D-_ -- SILYLATION

Pyridine was allowed to stand over potassium hydroxide pellets for 24 hours, then distilled from barium oxide and stored over 4A molecular sieves. Toluene was refluxed over sodium metal for three days, then distilled and stored over Linde type 4A molecular sieves. A reagent mixture of 20% pyridine, 15% dichlorodimethylsilane and 65% toluene was prepared and stored over the molecular sieves.

A 250 ml round bottomed flask equipped with magnetic stirring, a reflux condenser and argon inlet was flushed with dry argon and charged with 10 g of pulverized tectosilicate followed by addition of 100 ml of the reagent mixture described hereinabove. The resultant slurry was refluxed for 20 hours. After reaction, the acid-treated tectosilicate material was isolated by filtration and washed with dry toluene and methanol. The material was refluxed for at least two hours in methanol, recovered by filtration and stored under ambient conditions.

PROCEDURE D ₂ -- METHYLATION About 5.0 g of pulverized material was placed in a steel bomb with about 50 ml of methanol. The bomb was sealed and heated to 220°C for 4-12 hours. The bomb was cooled to 25°C and the material recovered by filtration.

Example 2 DETERMINATION OF GAS RETENTION VOLUMES

The treated, pulverized tectosilicate was vacuum- packed into a silylated glass column (0.125 inch inner diameter, 0.25 inch outer diameter) and held in by plugs of silylated glass wool. The column was inserted into the oven of a gas chromatograph. The injector port was maintained at 200°C, the detector oven at 250°C and the column maintained at an initial conditioning temperature of 45°-50°C for 10-30 minutes. The detector filament current was held at 150mA and the carrier gas (He) inlet pressure was 60 psi. Gas injections (75-125 μl) were made at 407 psi above ambient pressure and liquid injections were between 1-2 μl . Water and ammonia retention volumes were measured at a column temperature of 200°C. Under these conditions, ammonia was irreversibly adsorbed. Results were expressed as K (ml of gas adsorbed/g of adsorbent at STP) .

The properties of a number of modified Hector, California clinoptilolites prepared by various combinations of the procedures described above are summarized in Table I. In all cases the procedures were performed or omitted in the order indicated. The silicon:aluminum ratios were determined by energy- dispersive X-ray spectrometry (Tracor spectrace model

440, Tracor-Northern 2000 Analyzer) with data reduction accomplished using the program Super ML, Tracor X-Ray, Inc.

TABLE I

Total Carbon

Sample Treatment ¹ K(H ₂ 0) ² Si/Al Analysis (%) ⁵

1 none >200 10.00 0.28

2 A ₂ H ₁ D ₂ 21 High ³ 0.69

3 A ₂ H ₁ D ₁ 26 High ³ 0.62

4 A ₂ H ₁ D ₀ 36 211.67 0.12

5 A-H_D ₂ 58 39.58 0.52

6 AιH ₂ D ₀ 59 6.93 ⁴ 0.30

7 A ₁ H ₂ D ₁ 64 32.66 0.63

8 ^A 1 ^H 1 ^D 1 79 33.00 2.37

9 A.H^o 93 34.43 0.38

10 A ₁ H ₀ D ₂ 129 33.56 0.29

11 A _X E ₀ Ό ₀ >200 10.82 ⁴ N.T.

12 AiHøD _! >250 39.01 2.90

13 A _X H ₂ D ₂ >570 6.8 ⁴ 0.36

^■ ' ^■ Treatments A _1# A ₂ , H _χ , H ₂ , D _χ , and D ₂ are described in Example 1. D ₀ treatment indicates no derivatization; H ₀ treatment indicates no heat treatment.

² ml/g at STP: K(NH ₃ ) was >200 in all cases.

³ Lattice Al not detected in these materials. Anomalous results probably due to operator error.

⁵ Galbraith Laboratories, Inc., Knoxville, Tenn.

Table I illustrates that mild or strong acid washes followed by high or low temperature heating significantly increases the hydrophobicity of the tectosilicate even without a further derivatization step. The effect is most pronounced in the case of samples washed with strong acid, then heated at 150°C. (A ₂ H ₁ D ₀ , Sample 4) . However, samples 3 and 2 demonstrate that a further significant increase in hydrophobicity can be attained by silylation or methylation, respectively, of this material. The

total percent carbon is also increased in these samples by over 400% in each case. Likewise, an increase in hydrophobicity is observed in the case of the silylation (Sample 8) or methylation (Sample 5) of the material of Sample 9, which had been subjected to the mild acid wash and then to 150°C heating. The greater affinity for water observed for these samples, as opposed to samples 3 and 2, is thought to reflect the presence of more reactive sites, i.e., silyl nests, in the latter two materials, which had been exposed to stronger dealumination conditions.

Mild heat treatment before derivatization retains lattice structure and minimizes collapse of hydroxyl or other reactive sites. Sample 6 was made by mild acid treatment but high heat treatment . Derivation of sample 6 by silylation and methylation formed samples 7 and 13, respectively. However, samples 7 and 13 exhibit little or no increase in hydrophobicity relative to sample 6, indicating derivatization was ineffective. A comparison of samples 8 and 7, with 9 and 6 indicates that, for otherwise equivalently-prepared samples, a high heat treatment (H ₂ ) results in a significantly lower carbon incorporation when either methylation or silylation is attempted. While not wishing to be limited, poor derivatization may be due to the collapse of hydroxyl nests or other reactive sites by high heat treatment.

Silylation of material which had been acid washed but not dehydrated by heat (sample 12) failed to increase the hydrophobicity of the material of sample 11, possibly due to the blockage of reactive sites by water of hydration. Methylation of the same material caused a moderate increase in hydrophobicity (sample 10) . Thus, the activated nests following acid treatment are best produced and preserved by mild heat treatment. The hydrophobic derivatized materials of samples 3 and 2 possessed no detectable lattice aluminum by X-ray fluorescence, a negative result also expected and

observed in the case of silicalite ^® (Union Carbide) . This provides confirmation that the strong acid wash conditions are effective to remove lattice aluminum and produce reactive hydroxyl-containing nests that are available for derivatization. Although removal of lattice aluminum is, by itself, adequate to significantly increase the hydrophobicity of the clinoptilolite, and, in fact, is the major contributor to the hydrophobic properties involved, it is apparent from samples 8, 3, 5 and 2 that the hydrophobic properties are optimized, for this set of treatment variables, by further silylation or methylation. Significant hydrophobic affects are generally observed in both derivatized and nonderivatized materials when the Si:Al ratio exceeds about 25. The hydrophobic materials of samples 8, 3, 5 and 2 would be expected to adsorb significant amounts of ammonia from wet human or animal excreta, and to do so more effectively than any material employed heretofore, such as unmodified tectosilicates, phyllosilicate clays, silica gel and the like.

Example 4

Total Bacteriological Population in the Lungs of Chickens that Were Fed Zeolites

Methods: Batches of freshly hatched chicks were raised on feed containing deaiuminated clinoptilolite that was, in some cases, derivatized with DCDMS, in the amounts specified in Table II.

TABLE II Treatment ¹ Amount zeolite in feed

1 50 mg/lb DCDMS zeolite

2 250 mg/lb DCDMS zeolite

3a Control -- 125 mg/lb aluminated and nonderivatized zeolite

3b Control -- 125 mg/lb deaiuminated but nonderivatized zeolite 4 500 mg/lb DCDMS zeolite

5 125 mg/lb DCDMS zeolite

This feed was the only feed given to these chickens from the time of hatching until slaughter, which occurred at about 7-8 weeks of age. The chickens were examined by a veterinarian for symptoms of disease, malnutrition and poor growth. The histopathology of the chickens' hearts, livers, spleens, kidneys, trachea and lungs were also observed (see Tables III and IV) . While no overall toxic effects of this feeding regimen were observed, some lesions were observed in the trachea and lungs which were likely due to irritation or inhalation of foreign material (see Table IV) . The number of colony forming units per gram of lung tissue was determined to ascertain whether one group of chickens had an increased propensity for lung infections, e.g. bacterial pneumonia.

Results:

No negative effects upon the chickens were observed.

TABLE III HISTOPATH0L0GY REPORT: ZEOLITE EXPERIMENT #1

Heart - In most birds there were no alterations. A few had scattered and small infiltrations of lymphocytes between muscle bundles. Intimal proliferation in small arteries occurred in two birds.

Liver - The usual focal collections of lymphocytes were present in most of the livers. These foci were scattered in the parenchyma and in portal areas. In some birds the lymphocytes were mixed with immature granulocytes . The epithelium of occasional bile ducts was hypertrophic.

Spleen No remarkable lesions. Kidney Focal collections of lymphocytes, in follicular formation or diffuse infiltration, were scattered in the cortex or medulla of several birds.

Trachea An inflammation of varying severity involved the trachea of most birds. These lesions were characterized by infiltration of lymphocytes in the mucosa. The infiltrations were diffuse or follicular and involved focal are diffuse areas of the trachea. Little exudate was present in the lumen. The cilia were not involved.

Lung Nodular collections of lymphocytes occurred in the mucosa of bronchi in all lungs. Granulomas, consisting of

necrotic centers with surrounding lymphocytes, heterophiles and multinucleated giant cells, were present in the lumina of bronchi in many birds. Bacterial colonies were often present in the granulomas and mycelia were identified in two birds. Crystalline foreign material was observed in the lesions of one bird. Occasionally the infection had spread in the peribronchial tissue resulting in areas of pneumonia.

Foci of cartilage and/or bone were scattered in the parenchyma of many birds.

TABLE IV SUMMARY OF LESIONS

Tracheit Lung* is*

Av. Granu¬ Bact Fungus Pneu¬ Score ** loma monia

Tmt 1 12/24 0.51 5/24 1/24 1/24 0/24

Tmt 2 20/24 1.50 12/23 4/23 0/23 10/23

Tmt 3 18/24 1.25 10/24 5/24 0/24 6/24

Tmt 4 12/24 0.83 9/24 1/24 1/24 0/24

Tmt 5 17/24 0.95 6/24 4/24 0/24 6/24

* Number/Total

**Lesion Score (severity) 0 normal, 4 most severe.

There was no evidence of toxicity in these birds.

Only the lesions of the respiratory system were possibly related to the experiment . The lymphocytic infiltrations occurring in the liver, spleen and kidney are commonly observed in birds in the field. The occasional hyperplasia of the bile duct epithelium was not associated with the experimental treatment. Peri- ductal infiltrations of heterophiles are observed occasionally in field birds.

The lesions of the trachea and lung were those of irritation and/or inhalation of unidentified foreign material. Tracheitis was possibly the result of ammonia levels. The location of the granulomas in the lumina of bronchi suggested the lesions were related to inhalation. The lesions appeared to arise from some material or organism which had lodged on the mucosal surface.

Infection in some cases had spread to adjacent areas of the lung.

Chickens were tested to determine whether feeding derivatized zeolites had a negative impact upon the lung, e.g. by causing bacterial lung infections. The treatment regimen was provided in Table II. Table V summarizes the results.

TABLE V Effect of Feeding Chickens Clinoptilolite derivatized with DCDMS

TREATMENT ¹ REPL ² LUNG CFU/MAC ³

1-50 mg/lb 1 3000/gm

1-50 mg/lb 2 12000/gm

2 2--225500 1 450/gm mg/lb

2-250 2 800/gm mg/lb

3a- 1 60000/gm control ⁴

3b- 2 15000/gm control ⁵

4-500 1 115/gm mg/lb

4 4--550000 2 180/gm mg/lb

5-125 1 1500/gm mg/lb

5-125 2 12000/gm mg/lb Amount DCDMS-derivatized clinoptilolite in feed. ² Replicate number.

³ Number of colony forming units observed on a MacConkey agar plates per gram of lung tissue.

⁴ Control -- chickens were fed 125 mg/lb aluminated and nonderivatized zeolite. ⁵ Control -- chickens were fed 125 mg/lb deaiuminated and nonderivatized zeolite.

As illustrated in Table V, feeding increasing amounts of deaiuminated, derivatized zeolite to chickens decreases the number of colony forming units (CFU) in the lung. Chickens fed aluminated zeolites had 60,000 CFU per gram lung tissue. Chickens fed deaiuminated zeolites had five-fold fewer CFU. Hence, dealumination of zeolites fed to chickens causes a reduction in bacterial infection, even when the zeolites are not derivatized. Feeding deaiuminated zeolite therefore protected chickens against lung infection.

Example 5

Deaiuminated Zeolites Adsorb Ammonia As Well As Silanated Zeolites

Methods:

Deaiuminated zeolites were prepared as provided by the present invention. After dealumination some zeolites were derivatized also according to the present invention. The binding capacity for ammonia of these zeolites was tested by standard procedures.

Results:

Table IX summarizes the amount of ammonia, selectivity for ammonia and the binding capacity of the different zeolites. As illustrated, the unsilanated zeolites were just as selective for ammonia as the silanated zeolites. Moreover, the binding capacity of the unsilanated zeolites was as high as the silanated zeolites. Hence, zeolites which are properly deaiuminated are very effective ammonia adsorbents.