EP0796145A1

EP0796145A1 - Acid contacted enhanced adsorbent particle and method of making and using therefor

Info

Publication number: EP0796145A1
Application number: EP95943006A
Authority: EP
Inventors: Mark L. Moskovitz; Bryan E. Kepner
Original assignee: M & K Patent Co Inc; M AND K PATENT COMPANY Inc
Current assignee: Apyron Technologies Inc
Priority date: 1994-12-07
Filing date: 1995-12-06
Publication date: 1997-09-24
Also published as: AU4416796A; ZA9510401B; AU708178B2; JPH11511687A; TW427926B; CA2207039A1; IL116276A; WO1996017682A1; IL116276A0

Abstract

This invention relates to a process for producing an enhanced adsorbent particle comprising contacting a non-amorphous, non-ceramic, crystalline, porous, calcined, aluminum oxide particle that was produced by calcining at a particle temperature of from 400 °C to 700 °C, with an acid for a sufficient time to increase the adsorbent properties of the particle. A process for producing an enhanced adsorbent particle comprising contacting a non-amorphous, non-ceramic, crystalline, porous, oxide adsorbent particle with an acid for a sufficient time to increase the adsorbent properties of the particle is also disclosed. Particles made by the process of the instant invention and particle uses, such as remediation of waste streams, are also provided.

Description

ACID CONTACTED ENHANCED ADSORBENT PARTICLE AND METHOD OF MAKING AND USING THEREFOR

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

This invention relates generally to enhanced adsorbent particles, particularly particles that have been adsorbent enhanced by contacting with acid.

BACKGROUND ART

Oxides of metals and certain non-metals are known to be useful for removing constituents from a gas or liquid stream by adsorbent mechanisms. For example, the use of activated alumina is considered to be an economical method for treating water for the removal of a variety of pollutants, gasses, and some liquids. Its highly porous structure allows for preferential adsorptive capacity for moisture and contaminants contained in gasses and some liquids. It is useful as a desiccant for gasses and vapors in the petroleum industry, and has also been used as a catalyst or catalyst-carrier in chromatography and in water purification. Removal of contaminants such as phosphates by activated alumina are known in the art. See, for example, Yee, W., "Selective Removal of Mixed Phosphates by Activated Alumina," J.Amer. Walerworks Assoc, Vol. 58, pp.239-247 (1966).

U.S. Patent No. 4,795,735 to Liu et al. discloses an activated carbon alumina composite and a process for producing the composite. The composite is prepared by blending powders of each of the activated carbon and activated alumina constituents. After the blend is thoroughly mixed, an aqueous solution is added to permit the activated alumina to rehydratably bond to the carbon particles. The amount of water added does not exceed that which prevents the mix from being extruded or agglomerated. After the water is added, the mix is subjected to a shaping or a forming process using extrusion, agglomeration, or pelletization to form a green body. The green body is then heated to a temperature of 25- 100 ^βC or higher. The composite may be strengthened by peptizing by adding nitric acid to the mixture. It is disclosed that the alumina can serve as the binder as well as the absorbent. This patent does not use a calcined alumina. Liu et al. discloses an amorphous alumina trihydrate powder, such as CP2 obtained from Alcoa and an amorphous alumina trihydrate powder such as CP-1 or CP-7, which are recited in U.S. Patent No. 4,579,839, incorporated by reference in Liu et al. Liu et al. 's use of the term active refers to the surface water being dried and does not refer to a calcined particle. Liu et al. uses acid to strengthen the particle and not to enhance its adsorbent properties. Liu et al. uses an alumina precursor, which is an absorbent and not an adsorbent.

U.S. Patent No. 3,360,134 to Pullen discloses a composition having adsorption and catalytic properties. Example 2 discloses an alumina hydrate formed by partially dehydrating alpha-alumina trihydrate in a rotary dryer by counter-current flow with a heated gas and an inlet temperature of about 1200°F and an outlet temperature of about 300°F. The resulting product was washed with 5% sulfuric acid, rinsed with water and dried to about 2% free water content. Solid sucrose was mixed with the hydrate and the mixture heated. Example 4 discloses that the procedure of Example 2 was repeated except that calcined alumina was used. The product was unsuitable when calcined alumina was used. Thus, the acid washed product of Example 2 was not a calcined alumina.

U.S. Patent No. 4,051 ,072 to Bedford et al. discloses a ceramic alumina that can be treated with very dilute acid to neutralize the free alkaline metal, principally Na₂O, to enable impregnation with catalytic material to a controlled depth of from at least 90 to about 250 microns. This patent does not use a crystallized aluminum oxide that has been calcined in accordance with the instant invention. This patent calcines the particle at a temperature of from about 1700°F to about 1860°F (927^βC to 1016^βC) to form a ceramic material, specifically what is referred to herein as an alpha alumina. U.S. Patent No. 5,242,879 to Abe et al. discloses that activated carbon materials, which have been subjected to carbonization and activation treatments, and then further subjected to an acid treatment and a heat treatment, have a high catalytic activity and are suitable as catalysts for the decomposition of hydrogen peroxide, hydrazines or other water pollutants such as organic acids, quaternary ammonium-salts, and sulfur-containing compounds. Acid is used to remove impurities and not to enhance the adsorbent features. This patent also does not utilize a particle of the instant invention.

Adsorbent particles of the prior art have not achieved the ability to remove particular contaminants from a liquid or gas stream, such as. for example, a waste stream or drinking water, to acceptably low levels. Additionally, the adsorbent particles of the prior .art have not been able to bind tightly to particul.ar contaminants so that the adsorbent particle/contaminant composition can be safely disposed of in a landfill. Thus, there has been a need in the art for adsorbents that have improved ability to adsorb particular materials, particularly contaminants from a gas or liquid stream, to thereby purify the stream. There has been a need in the art for the adsorbent particles to tightly bind to the adsorbed contaminant.

SUMMARY OF THE INVENTION

In accordance with the purpose(s) of this invention, as embodied and broadly described herein, this invention, in one aspect, relates to a process for producing an enhanced adsorbent particle comprising contacting a non-amorphous, non-ceramic, crystalline, porous, calcined, aluminum oxide particle that was produced by calcining at a particle temperature of from 400° C to 700° C, with an acid for a sufficient time to increase the adsorbent properties of the particle.

The invention further provides a process for producing an enhanced adsorbent particle comprising contacting a non-amorphous, non-ceramic, crystalline, porous, oxide adsorbent particle with an acid for a sufficient time to increase the adsorbent properties of the particle.

In yet another aspect, the invention provides for particles made by the process of the instant invention.

In yet another aspect, the invention provides for a process for reducing or eliminating the amount of contaminants in a stream comprising contacting the particle of the invention with the stream for a sufficient time to reduce or eliminate the contamination from the stream.

In still yet another aspect, the invention provides a composition comprising the particles of the invention.

Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements .and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the Examples included therein.

Before the present compositions of matter and methods are disclosed and described, it is to be understood that this invention is not limited to specific synthetic methods or to particular formulations, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

In this specification and in the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings:

The singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise.

"Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

The term "particle" as used herein is used interchangeably throughout to mean a particle in the singular sense or a combination of smaller particles that are grouped together into a larger particle, such as an agglomeration of particles.

The term "ppm" refers to parts per million and the term "ppb" refers to parts per billion.

In accordance with the purpose(s) of this invention, as embodied and broadly described herein, this invention, in one aspect, relates to a process for producing an enhanced adsorbent particle comprising contacting a non-amorphous, non-ceramic, crystalline, porous, calcined, aluminum oxide particle that was produced by calcining at a particle temperature of from 400° C to 700° C, with an acid for a sufficient time to increase the adsorbent properties of the particle. This process can also consist essentially of or consist of the particular process steps as described above or further including the additional features described below.

The invention further provides a process for producing an enhanced adsorbent particle comprising contacting a non-amorphous, non-ceramic, crystalline, porous, oxide adsorbent particle with an acid for a sufficient time to increase the adsorbent properties of the particle. This process can also consist essentially of or consist of the particular process steps as described above or further including the additional features described below.

In yet another aspect, the invention provides for p-articles made by the process of the instant invention.

The particles of this invention have improved or enhanced adsorptive features. The particles of this invention can adsorb a larger amount of adsorbate per unit volume or weight of adsorbent particles than a non-enhanced particle. Also, the particles of this invention can reduce the concentration of contaminants or adsorbate material in a stream to a lower absolute value than is possible with a non-enhanced particle. In particular embodiments, the particles of this invention can reduce the contaminant concentration in a stream to below detectable levels, never before achievable with prior art particles. Enhanced adsorptive features is intended to include both ion capture and ion exchange mechanisms. Ion capture refers to the ability of the particle to bond to other atoms due to the ionic nature of the particle. Ion exchange is well known in the art and refers to ions being interchanged from one substance to another. Adsorption is a term well known in the art and should be distinguished from absorption. The adsorbent particles of this invention chemically bond to and very tightly retain the adsorbate material. US95/15 29

- 7 -

Not wishing to be bound by theory, it is believed that the acid contacting of the particle enhances the adsorptive capacity of the particle by adding onto the surface of the particle pores ion moieties present in the acid or present in particle surface water, such as OHM PT*^", and/or the anion of the acid. The particle covalently or ionically bonds to these ions. It is believed that the particle exhibits an excess and thus an increased charge in comparison to non-enhanced particles.

In the particle of this invention, typically any adsorbent particle that is non- amorphous, non-ceramic, crystalline, porous, has oxygen in the crystal lattice, and can hold a charge, can be used. The particles of this invention are in the crystalline form and are therefore non-amorphous. Adsorbent particles that are very rigid or hard, are not dissolved to any detrimental degree by the acid, and which have initially high, pre- enhanced adsorptive properties are preferred. Examples of such particles include, but are not limited to, metal oxides, such as transition metal oxides and Group IIIA and Group IVA metal oxides, and oxides of non-metals such as silicon and germanium. Preferred adsorbents include oxides of aluminum, silicon, manganese, copper, vanadium, zirconium, iron, and titanium. Even more preferred adsorbents include aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), manganese oxides (MnO, MnO₂, Mn₂O₃, and Mn₃O₄), copper oxides (CuO and Cu₂O), vanadium pentoxide (V₂O₅), zirconium oxide (ZrO₂), iron oxides (FeO, Fe₂O₃, and Fe₃O₄), and titanium dioxide (TiO₂). In an even more preferred embodiment, the oxide is aluminum oxide (Al₂O₃) that has been produced by calcining at a particle temperature of from 400 ^βC to 700 "C. These preferred aluminum oxide particles are preferably in the gamma, chi-rho, or eta forms. The ceramic form of Al₂O₃, such as the alpha form, are not included as a part of this invention. In a preferred embodiment, the Al₂O₃ particles of this invention have a pore size of from 3.5 nm to 35 n (35A to 350 A) diameter and a BET surface area of from 120 to 350 m²/g.

In one embodiment, the particle is aluminum oxide that has been pre-treated by a full calcination process. Calcined aluminum oxide particles are well known in the art. They are particles that have been heated to a particular temperature to form a particular crystalline structure. Processes for making calcined aluminum oxide particles are well known in the art as disclosed in, e.g., Physical and Chemical Aspects of Adsorbents and Catalysts, ed. Linsen et al., Academic Press (1970), which is incorporated by reference herein. In one embodiment, the Bayer process can be used to make aluminum oxide precursors. Also, pre-calcined aluminum oxide, that is, the aluminum oxide precursor (Al(OH)₃), and calcined aluminum oxide are readily commercially available. Calcined aluminum oxide can be used in this dried, activated form or can be used in a partially or near fully deactivated form by allowing water to be adsorbed onto the surface of the particle. However, it is preferable to minimize the deactivation to maximize the adsorbent capability. In some references in the prior art, "activated" refers only to the surface water being removed from the particle to increase its adsorbent ability. However, as used in reference to the instant invention, activated refers to a particle that has first been calcined and is then also maintained in its dried state. Thus, as used herein, all active particles of the invention have also been calcined. The particles are not limited to any physical form and can be in the particulate, powder, granular, pellet, or the like form. The particles are preferably in a gel state.

The acid that can be used in this invention can be any acid or mixture of acids that can add extra ion moieties onto the surface of the pores of the oxide particle. Typical ion moieties include OHM H^"M and the anion of the acid. Examples of such acids include, but are not limited to. nitric acid, sulfuric acid, hydrochloric acid, boric acid, acetic acid, formic acid, phosphoric acid, and mixtures thereof. In a preferred embodiment, the acid is acetic acid because it is relatively safer to handle than most other acids and because of its cost effectiveness.

Typic-ally the acid is diluted with water to prevent dissolution of the particle and for cost effectiveness. In general, only a dilute solution of the acid is required to achieve maximum or saturated loading of the ion moieties on the particle. For example, a 0.5 wt. % and even a 0.1 % acetic acid solution has been found effective. However, a wide range of concentrations of acid can be used in this invention from very dilute to very concentrated depending on the hazards involved and the economics of production. However, if the acid is too concentrated, it will etch the particle causing an increase in macropores while eliminating micropores, which is detrimental to the particles of this invention. Thus, the acid treatment is preferably of a concentration and length of time to be more than a mere surface wash but less than an etching. Additionally, the acid preferably has some water present to provide OH^" and or H^* ion moieties, which bond with the particle. When the acid is diluted with water, the water is preferably distilled water to minimize the amount of impurities contacting the particle.

The particle of the invention is made by the following process. The particle is contacted with an acid. The particle can be contacted with the acid by various means including by the particle being dipped in, extensively washing with, or submerged in the acid. The length of time the particle must be contacted with the acid varies according to the ability of the particular particle to be saturated with the ion moieties. The time can be as low as a few minutes, at least 15 minutes, at least one hour, at least 6 hours, at least 12 hours, or at least one day, to assure saturation. The time must be sufficient to at least increase the adsorbent properties of the particle by adding ion moieties to the particle. In one embodiment, the particle is submerged in the acid, and saturation is typically complete when the particle stops bubbling. The contacting should be substantial enough to provide penetration of the acid throughout the pores of the particle. Mere washing the outside surface of the particle to remove impurities is not sufficient to provide adequate penetration of the acid into and throughout the pores of the particle.

The acid contacted particle is then optionally rinsed. Rinsing insures that the particle does not later release acid concentrated dust that may become airborne and which can be inhaled. Rinsing of the acid contacted particle does not reduce the enhanced adsorptive capability of the particle. When rinsed, the particle is preferably rinsed with distilled water to minimize impurity contact. Optionally, the particle is dried by a low to moderate heat treatment to remove excess liquid, such as acid or water, from the rinsing step to thereby increase the activity of adsorption. Drying of the particle also reduces the transfer cost of particle. However, the particle is not calcined or recalcined after acid treatment. Such recalcining would detrimentally change the surface characteristics by closing up the micropores.

The size of the particles used in this invention can vary greatly depending on the end use. Typically, for adsorption or catalytic applications, a small particle size such as 20 μm or greater are preferable because they provide a larger surface area than large particles.

The particle of this invention can be used in any adsorption or ion capture application known to those of ordinary skill in the art. In one embodiment, the particle is used for environmental remediation applications. In this embodiment, the particle can be used to remove contaminants, such as heavy metals, organics, including hydrocarbons, inorganics, or mixtures thereof. Specific examples of contaminants include, but are not limited to, acetone, microbials such as cryptosporidium, ammonia, benzene, chlorine, dioxane, ethanol, ethylene. formaldehyde, hydrocarbon cyanide, hydrogen sulfide. methanol, methyl ethyl ketone. methylene chloride, propylene, styrene. sulfur dioxide, toluene, vinyl chloride, arsenic, lead, iron, phosphates, selenium, cadmium, uranium, radon, l,2-dibromo-3-chloropropane (DBCP), chromium, tobacco smoke, cooking fumes, zinc, and trichloroethylene. The particle of this invention can remediate individual contaminants or multiple contaminants from a single source. In essence, anywhere ions are used to capture pollutants, this invention achieves improved efficiency by adsorbing a higher amount of contaminants and by reducing the contamination level to a much lower value than by non-enhanced particles.

For environmental remediation applications, particles of the invention are typically placed in a container, such as a filtration unit. The contaminated stream enters the container at one end, contacts the particles within the container, and the purified stream exits through another end of the container. The particles contact the contaminants within the stream and bond to and remove the contamination from the stream. Typically, the particles become saturated with contaminants over a period of time, and the particles must be removed from the container and replaced with fresh particles. The contaminant stream can be a gas stream or liquid stream, such as an aqueous stream. The particles can be used to remediate, for example, waste water, production facility effluent, smoke stack gas, auto exhaust, drinking water, and the like.

The particle of the invention can be used alone, in combination with other particles prepared by the process of the invention, and/or in combination with other adsorbent particles known in the art. The particles can be combined in a physical mixture or agglomerated using techniques known in the art. such as with a binder, to form a multifunctional composite particle.

In one embodiment, the invention is directed to a composition comprising an aluminum oxide particle made by the acid enhancing process of the invention. In a further embodiment, this composition further comprises a co-adsorbent particle. This co-particle is preferably any adsorbent particle known in the art. Such co-adsorbent particles can be preferably non-amorphous, non-ceramic, crystalline, porous, oxide adsorbent particles, more preferably silicon dioxide, or a metal oxide, such as manganese oxides (MnO, MnO₂, Mn₂O₃, and Mn₃O₄), copper oxides (CuO and Cu₂O), vanadium pentoxide (V₂O₅), zirconium oxide (ZrO₂), iron oxides (FeO, Fe₂O₃, and Fe₃O₄), and titanium dioxide (TiO₂). The co-particle can acid-enhanced or non-acid enhanced. In a preferred embodiment, the co-particles are not acid-enhanced.

In a preferred embodiment, the composition comprises aluminum oxide made by the acid enhanced process of the invention, copper oxide, and manganese oxide. Preferably, these components are in a proportion of from 50-98 parts, more preferably 80-95 parts, even more preferably 88 parts acid enhanced aluminum oxide; and 1-49 parts, more preferably 4- 19 parts, even more preferably 6 parts of each of copper oxide and manganese oxide. Preferably, the composition is held together using a colloidal alumina binder that has been crosslinked as described below. In a preferred embodiment, this composition can be used to remediate organics. such as hydrocarbons, even more preferably, trichloroethylene (TCE).

Not wishing to be bound by theory, it is believed that at least some and possibly all of the ability of the acid-enhanced aluminum oxide/co-particle embodiment of the invention to remediate organic contaminants is due to a catalytic degradation of the organic contaminant, even at room temperature. This catalytic activity is possibly present because the inventive co-particle was challenged with a high concentration of organic contaminants and no organic contaminants were found on the surface of the particle by visual observation or on the residual solution after TCLP analysis. In a preferred embodiment, the Al₂O₃ in combination with one or more oxides of manganese, copper, and/or iron are particularly suited to possibly catalytically degrade organics, such as hydrocarbons and trichloroethylene.

Binders for binding the individual particles, either of the same or different types, to form an agglomerated particle are known in the art or are described herein. Binders that do not interfere with the adsorbent features are preferred. In a preferred embodiment, the binder can also act as an adsorbent. A preferred binder for the agglomerated particle is colloidal alumina or colloidal silica. At approximately 450 °C, the colloidal alumina goes through a transformation stage and cross-links with itself. Colloidal silica cross-links with itself if it is sufficiently dried to remove water. Preferably, from about 5 wt% to about 99% of the total adsorbent particle mixture is colloidal alumina or colloidal silica to provide the necessary crosslinking during heating to bind the agglomerated particle into a water-resistant particle. The particle can then withstand exposure to all types of water for an extended time and not degrade.

In one embodiment, the agglomerated particle is made by mixing colloidal alumina with the adsorbent particles of the invention. Preferably, the acid enhanced particles have been produced and are ready for agglomeration prior to mixing with the acid below. Typically, from about 5% to about 99%, more preferably 20%, by weight of the mixture is colloidal alumina. The particle mixture is then mixed with .an acid solution such as, for example, nitric, sulfuric, hydrochloric, boric, acetic, formic, phosphoric, and mixtures thereof. In one embodiment the acid is 5% nitric acid solution. The colloidal alumina, adsorbent particles, and acid solution are thoroughly mixed so as to create a homogenous blend of all elements. Then additional acid solution is added and further mixing is performed until the mixture reaches a suitable consistency for agglomeration. Preferably, the mixture is then extruded and chopped up into the desired size. The resultant particles are heated to at least 450 °C to cause the colloidal alumina crosslinking to occur.

The particle of this invention bonds with the contaminant so that the particle and contaminant are tightly bound. This bonding makes it difficult to remove the contaminant from the particle, allowing the waste product to either be disposed of into any public landfill or used as a raw material in the building block manufacturing industry. Measurements of contaminants adsorbed on the particles of this invention using an EPA Toxicity Characteristic Leachability Procedure (TCLP) test known to those of skill in the art showed that there was a bond at least as strong as a covalent bond between the particles of this invention and the contaminants.

Experimental

The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds claimed herein are made and evaluated, and are intended to be purely exemplary of the invention and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.) but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C and pressure is at or near atmospheric. Example 1.

Enhanced aluminum oxide particles were made by the process of this invention. Gamma aluminum oxide particles were produced by calcining Al(OH)₃ at a particle temperature of 550-560°C. 20 liters of this aluminum oxide were submerged in a tank containing 0.5% by weight acetic acid in distilled water. The total volume of solution was 15.56 liters. The alumina was allowed to sit for approximately 15 minutes to allow saturation of the solution. The acid solution was drained off and the remaining alumina was rinsed in a tank of 30 liters of distilled water. The distilled water was drained and the remaining alumina was dried at a temperature of 121 °C for 90 minutes.

The performance of enhanced aluminum oxide particles of this invention was tested. Two chromatographic columns, each 25 cm. long and 1 cm. inner diameter, equipped with a solvent reservoir were used for this experiment. Each column was packed with 20 cc of the above produced enhanced aluminum oxide particles. Each column was flushed with 100 ml of water using pressure from the a nitrogen cylinder to obtain a flow rate of approximately 20 ml per minute. A test solution of approximately 200 ppb of lead was prepared using lead acetate trihydrate. A total of 200 ml (10 bed volumes) of test solution was passed through each column using the same flow rate. The influent, the total effluent from the 10 bed volumes, and the effluent sample collected during the tenth bed volume were analyzed for lead. The results -are set forth in Table 1 below.

TABLE 1

TEST NUMBER STREAM TESTED TOTAL LEAD'

(μgm/liter)

1 Influent 211

Total effluent < 5

Effluent end (10th bed volume) <5

2 Influent 229

Total effluent <5

Effluent end (10th bed volume) <5

^* Lower limit of lead detection was 5 μgm/liter.

Example 2.

A comparison was made between alumina of this invention and non-treated alumina for removing lead. Enhanced gamma aluminum oxide particles of the present invention were made according to the procedures of Example 1. Two identical five gallon containers were filled with the alumina oxide for lead removal. One container was filled with 16 liters of the treated alumina of this invention. The other was filled with 16 liters of untreated alumina. Two tanks were prepared each containing 100 gallons of lead acetate tri-hydrate spiked distilled water. The tanks were mixed thoroughly for 30 minutes. After 30 minutes of mixing, the concentrations of the lead in the water were determined. The lead containing water from each tank was passed through the containers of alumina. A total of 80 gallons of spiked water (16 bed volumes) were passed through each of the containers at a flow rate of 62 gallons per minute. An effluent water sample was taken on the 16th bed volume and was analyzed for total lead. The percent reductions were then calculated. The results of the tests are set forth in Table 2 below. TABLE 2

PARTICLE INITIAL LEAD EFFLUENT PERCENT CONCENTRATION CONCENTRATION REDUCTION

(mg 1) AFTER CONTACTING OF LEAD

PARTICLE (%)

(mg 1)

Non-treated 1.24 0.58 47 aluminum oxide

Treated aluminum 1.44 0.39 74 oxide of the invention

Example 3.

A comparison was made between treated alumina of this invention and non- treated alumina for removing phosphate. Chi-rho aluminum oxide particles were produced by calcining Al(OH)₃ at a particle temperature of 480-520°C. Enhanced chi- rho aluminum oxide particles of the present invention were then made according to the procedures of Example 1. The performance of the particles was measured using the same procedures of Example 1, except that one chromatographic column was filled with 20 cc of the treated alumina and the other column was filled with 20 cc of the untreated alumina and the test solution was 9.3 mg 1 of KH₂PO₄. The results of the tests are set forth in Table 3 below.

TABLE 3

PARTICLE INITIAL EFFLUENT PERCENT

PHOSPHATE CONCENTRATION REDUCTION

CONCENTRATION AFTER CONTACTING OF

(mg/1) PARTICLE PHOSPHATE

(mg/I) (%)

Non-treated 9.3 0.16 98.3 aluminum oxide

Treated aluminum 9.3 0.04 99.6 oxide of the invention

Example 4

The ability of the particle of this invention to remove selenium was tested. Acid enhanced gamma aluminum oxide particles (100% Al₂O₃) were made by the procedure of Example 1.

5 columns were prepared using 0.875" I.D. x 12" long glass columns, each with a bed volume of -95 mis of the above acid enhanced Al₂O₃ particles of this invention of various particle sizes, ranging from 500 μm to 4,000 μm. Each bed was flushed with -5 bed volumes of I.D. water by downward pumping at 5-6 gpm/ft cross sectional flow rate (i.e., -95 ml/min). A test solution was prepared with a calculated 1.5 mg/L selenium. A total of - 10 bed volumes (i.e., - 1 L per column) test solution was pumped through each column using the same flow rate. During the test, the test solution was continuously stirred at a low speed. During the tenth bed volume, an effluent sample from each column was collected and analyzed for selenium. Also a single influent sample was collected and analyzed for selenium. The results are set forth below. Sample I.D. Total Selenium³ (particle size μm) mg L

Influent 1.45

606 EFF (4,000 μm) 0.101

404 EFF (1,000 μm) 0.073

303 EFF (2,000 μm) 0.477

202 EFF (500 μm) 0.003^b

101 EFF (3,300 μm) 0.121

Selenium detection limit was 0.002 mg/1 Estimated value, less than calibration limit

Example 5

A combination particle of this invention was made and tested for its ability to remove trichloroethylene. 70 g of acid enhanced gamma aluminum oxide particles made by the procedure of Example 1 were mixed with 20 g of alumina type gel, 5 g of Mn₂O , and 5 g of CuO until the mixture was homogeneous. The particle mixture was then mixed with 5% nitric acid solution until the mixture reached a suitable consistency for agglomeration. The mixture was extruded and cut into a particle size of about 1,000 μm and heated to 500 "C for 15 minutes to crosslink the colloidal alumina.

Two chromatographic columns (24 cm x 8 mm) each containing 3 ml (dry) volumes of the above produced Al₂O₃/CuO/Mn₂O₃ combination particle of the invention were charged with 5 x 1 bed volume of (a) 1 ppm trichloroethylene (TCE) in deionized water and (b) 1 ppm VOA matrix spike mix (also containing 1 ppm TCE) in deionized water, respectively. The 1 ppm VOA stock solution was obtained by dilution (deionized water) of a 1000 μg ml VOA mix (Supelco) which contained the following analytes in methanol; (1) benzene, (2) chlorobenzene, (3) toluene, (4) trichloroethylene, and (5) 1,1-dichloroethylene. The other stock solution (1 ppm TCE in water) was obtained by dissolving 0.01 g spectrophotometric grade TCE (Aldrich) in deionized water followed by dilution to a liter. The fifth bed volume from each column was collected (no headspace) in 2 ml screw-cap vials with Teflon-coated silicone septa and stored on ice prior to GC/MS analysis (EPA Method 8260). The results are as follows.

Trichloroethylene concentration

Sorbate

Influent (ppm) Effluent (ppb)

TCE in water 1.0 <50

VOA mix in water 1.0 <50

Example 6

TCE adsorption and TCLP extraction procedures were performed as follows. A 20.0114-gram (about 24.50 bed volume) sample of the Al₂O₃/CuO/Mn₂O₃ combination particle of Example 5 (designated as 0307595TCE1 ) was wet packed into a 50-mL buret (with removable stopcock) plugged with glass wool. The sample was charged with five bed volumes of water. The sorbent material was then quantitatively transferred into the Zero Headspace Extractor (ZHE) apparatus into which 200 mL of water was added, appropriately sealed and agitated for 18 hours. The filtered solution was collected in two 100 mL vials, stored in the refrigerator at 4^βC until analysis by GC/MS. The Finnigan MAT Magnum ion trap GC/MS equipped with a Tekmar liquid sample concentrator (LSC 2000) was used for analysis.

The calibration curve procedure was as follows. A freshly prepared 50 ppm TCE stock solution was obtained by dissolving 34.2 μl spectrophotometric grade TCE (Aldrich) in 20 ml HPLC grade methanol (Fisher) followed by dilution to a liter. Dilution of this solution (1000 μl : 1L) resulted in a 50 ppb TCE stock solution. All dilutions were accomplished using deionized water. A calibration curve was constructed by purging 1.0, 0.50, 0.20, 0.10, and 0.050 ppb TCE solutions.

The results are set forth below.

Sorbent Sample TCE found, ppb TCE Detection limit, ppb

0307595TCE1 Nd^a 0.0050

^a = Not detected. The fact that TCE in the sample is less that 500 ppb (EPA TCLP limit) characterizes it as a nonhazardous waste with respect to TCE.

Throughout this application, various publications are referenced. The disclosure these publications in their entireties are hereby incorporated by reference into this applica in order to more fully describe the state of the art to which this invention pertains.

It will be apparent to those skilled in the art that various modifications and variatio can be made in the present invention without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

What is claimed is:

1. A process for producing an enhanced adsorbent particle comprising contacting a non- amorphous, non-ceramic, crystalline, porous, calcined, aluminum oxide particle that was produced by calcining at a particle temperature of from 400" C to 700" C, with an acid for a sufficient time to increase the adsorbent properties of the particle.

2. The process of Claim 1, wherein the acid comprises acetic, nitric, sulfuric, hydrochloric, boric, formic, or phosphoric acid, or mixtures thereof.

3. The process of Claim 1, wherein the acid comprises acetic acid.

4. The process of Claim 1, wherein the contacting is by dipping or submerging the particle in acid.

5. The process of Claim 1, further comprising the step of rinsing the particle to remove excess acid.

6. The process of Claim 5, further comprising the step of drying the particle.

7. The process of Claim 1 , wherein the contacting is for at least 15 minutes.

8. The process of Claim 1 , wherein the resultant acid treated aluminum oxide is not recalcined.

9. A process for producing an enhanced adsorbent particle comprising contacting a non- amorphous, non-ceramic, crystalline, porous, oxide adsorbent particle with an acid for a sufficient time to increase the adsorbent properties of the particle.

10. The process of Claim 9, wherein the oxide adsorbent particle is not aluminum oxide.

11. The process of Claim 9, wherein the oxide adsorbent particle is silicon dioxide, manganese oxide, copper oxide, vanadium pentoxide, zirconium oxide, iron oxid titanium dioxide

12. The particle made by the process of Claim 1.

13. The particle made by the process of Claim 3.

14. The particle made by the process of Claim 9.

15. The particle made by the process of Claim 11.

16. The particle of Claim 12, wherein said particle passes the EPA TCLP test for a particular contaminant.

17. The particle of Claim 16, wherein said contaminant is lead.

18. A process for reducing or eliminating the amount of contaminants in a liquid or g stream comprising contacting the particle of Claim 12 with the liquid or gas strea for a sufficient time to reduce the amount of or eliminate the contamination from t liquid or gas stream.

19. The process of Claim 18, wherein the stream is liquid.

20. The process of Claim 18, wherein the stream is gas.

21. The process of Claim 18, wherein the contaminant is lead, phosphate, selenium, or zinc.

22. A composition comprising the aluminum oxide particle made by the process of Claim 1.

23. The composition of Claim 22, further comprising a second oxide adsorbent particle.

24. The composition of Claim 23, further comprising an aluminum oxide gel binder.

25. The composition of Claim 22, further comprising silicon dioxide, manganese oxide, copper oxide, vanadium pentoxide, zirconium oxide, iron oxide or titanium dioxide,

26. The composition of Claim 22, further comprising copper oxide and manganese oxide.

27. The composition of Claim 26, wherein the composition comprises 50-98 parts of said enhanced aluminum oxide, 1-49 parts of said copper oxide, and 1-49 parts of said manganese oxide.

28. The composition of Claim 26, wherein said composition passes the EPA TCLP test for trichloroethylene.

29. The composition of Claim 26, wherein said copper oxide is CuO and said manganese oxide is Mn₂O₃.

30. A process for reducing or eliminating the amount of an organic contaminant in a liquid or gas stream comprising contacting the composition of Claim 26 with the liquid or gas stream for a sufficient time to reduce the amount of or eliminate the organic contaminant from the liquid or gas stream.

31. The process of Claim 30, wherein the organic contaminant is trichloroethylene.

32. The process of Claim 30, wherein said reduction or elimination is by a catalytic degradation process.