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WO2000001459A1 - Composite a base de zeolithe de petit diametre, stable a l'eau, utile comme materiau echangeur d'ions - Google Patents

Composite a base de zeolithe de petit diametre, stable a l'eau, utile comme materiau echangeur d'ions Download PDF

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Publication number
WO2000001459A1
WO2000001459A1 PCT/US1999/015022 US9915022W WO0001459A1 WO 2000001459 A1 WO2000001459 A1 WO 2000001459A1 US 9915022 W US9915022 W US 9915022W WO 0001459 A1 WO0001459 A1 WO 0001459A1
Authority
WO
WIPO (PCT)
Prior art keywords
particles
zeolite
ion exchange
particle size
water
Prior art date
Application number
PCT/US1999/015022
Other languages
English (en)
Inventor
Evan E. Koslow
Original Assignee
Kx Industries, L.P.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kx Industries, L.P. filed Critical Kx Industries, L.P.
Publication of WO2000001459A1 publication Critical patent/WO2000001459A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J39/00—Cation exchange; Use of material as cation exchangers; Treatment of material for improving the cation exchange properties
    • B01J39/08—Use of material as cation exchangers; Treatment of material for improving the cation exchange properties
    • B01J39/14—Base exchange silicates, e.g. zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J47/00—Ion-exchange processes in general; Apparatus therefor
    • B01J47/018—Granulation; Incorporation of ion-exchangers in a matrix; Mixing with inert materials
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange

Definitions

  • This invention relates to the use of zeolite composites as ion exchange materials. More particularly, it involves forming small diameter zeolite composites with average particle sizes of about 10 ⁇ m to about 180 ⁇ m utilizing a low shear process. The particles are particularly efficient as ion exchange materials for the removal of heavy metals from solutions.
  • Zeolites have long been used as ion exchange materials.
  • An ion exchanger removes unwanted ions from a solution by transferring the unwanted ions to the ion exchange material and transferring an equivalent number of desired species from the ion exchange material to the solution. When the ion exchange material is full of the unwanted species, it either must be discarded or regenerated by washing the ion exchange material with the desired ion species.
  • ion exchangers A practical use for ion exchangers is the home water softening industry where the ion exchange material is used to soften water by removing calcium and magnesium and replacing them with a more desired species such as sodium.
  • Another significant area in which ion exchangers are used is the removal of heavy metals from potable water.
  • the contamination of drinking water by heavy metals, especially lead, has become an especially important health issue for the country.
  • the Environmental Protection Agency (EPA) stated that there is no safe threshold level of lead in drinking water and estimates that there is over 100 million people in the United States at risk from some degree of lead poisoning. Sources of lead poisoning include industrial wastes contamination, and lead bearing plumbing.
  • the avalanche effect is when the concentrated ions in the exhausted ion exchange material are suddenly released into the water. If the ions are lead, then this could lead to a significant health hazard.
  • zeolites have been studied for their potential use in the removal of toxic heavy metals and especially soluble lead.
  • natural zeolites often have low theoretical ion exchange capacities, reduced kinetics for adsorption and have limited specificity for lead compared to other non-targeted ions such as iron, magnesium, calcium, and mono-valent alkaline metal ions.
  • amorphous metal silicate gels as ion exchange materials which are formed by precipitating hydrous metal oxides, or by co-gelation of certain metal salts with silica or phosphate ions. It is generally believed that the kinetics for metal silicate gels are too slow for potable water applications.
  • Dodwell et al. disclose in U.S. Patent 5,053,139 that specific compositions of amorphous titanium and tin silicates have surprising fast kinetics that can be used for tap water ion exchange devices.
  • the problem with the metal oxide gels is that they have low mechanical strength. For example, it has often been experienced that when the particles are placed in an aqueous solution and vigorously stirred, the metal-oxide gel particles become finer and are difficult to separate from the aqueous solution. Likewise, when the metal oxide gels are deployed in a packed column, it is hard to prepare particles having a predetermined size. Even if such particles can be prepared, the particles become finer during contact with the aqueous solution and it becomes difficult to keep the particles from migrating into solution.
  • one object of the present invention is to provide ion exchange material having reaction kinetics that are suitable for household potable water applications.
  • Another object of the present invention is to provide ion exchange materials that have high mechanical strength and that can be incorporated into carbon block water purifiers.
  • Still another object of the present invention is to provide a method for producing the ion exchange material with the proper diameter, which can be used in conjunction with carbon block purifiers so that the ion exchange material will not migrate out into solution.
  • the present invention relates to the production of zeolite particle composites that have average diameters in the range of about 10 ⁇ m to 180 ⁇ m. These diameters are especially suitable for the production of carbon block filters used in household potable water applications.
  • the composite particles are produced by mixing 4 to 5 A commercial zeolite with water and organic or inorganic binders. The particles are then calcined at high temperatures to remove water and organic binder, which results in a water- stable structure. The particles are then ground in a low-shear grinder under extremely precise control to produce a high yield of product with particle sizes that are suitable for use with carbon block purifiers and other composite filter elements.
  • This invention relates to the use of zeolites that are used as ion exchange materials primarily in household water purification applications.
  • a wide variety of synthetic and natural zeolites may be used.
  • a typical zeolite is a inorganic aluminosilicate material with ion exchangeable cations and loosely held water molecules as shown in formulas I and II below:
  • zeolites that are commercially available such as
  • the binders can be an inorganic binder such as clay, a synthetic alkali metal silicate which is discussed in Hertzenburg, (U.S. Pat No. 4.613,578), and which is incorporated herein by reference, or an organic binder.
  • the resulting slurry can be tumbled in a revolving container, disk pelletized, or when suitably diluted sprayed to form particles in a range between 8 to about 80 mesh.
  • the resulting material is calcined at temperatures typically in the range between about 225°C to 525°C to remove the water and organic binder. After calcination, the composite material is water stable.
  • the inventors have discovered that these composite materials are far too large for use in a carbon block structure for household water purification because the kinetics of adsorption are far too slow.
  • the inventors have determined that the size of the composite material should be in the range of between about 10 ⁇ m to about 180 ⁇ m, preferably in the range of between about 10 ⁇ m to 150 ⁇ m, more preferably in the range of between about 20 to 100 ⁇ m and most preferably in the range of between about 30 to 50 ⁇ m.
  • the important aspect of this invention is that the composite material is reduced in size by a low shear grinding process so that the zeolite-binder matrix remains essentially intact.
  • This invention defines low shear grinding as a method where particles are subjected to compressive stress sufficient to cause fracture of the particles and where shear, involving the transverse application of force, is minimized.
  • a roll crusher provides significant compressive force and minimal shear, while a disk mill applies significant shear and very little compressive force.
  • the concept, according to the present invention is to cause the particles to fracture without further disintegration of the resulting particle. It is important to minimize the frictional forces that will cause the shearing of the zeolite-binder bonds. Rubbing, tumbling, ball milling and attrition milling would be inappropriate.
  • the present inventors have discovered that high shear grinding results in a disruption of the zeolite-binder bonds, which leads to a high volume of small particles and a low yield of particle sizes in the preferred range. As mentioned previously, these small particles can not be efficiently maintained in the carbon block material
  • Any suitable low shear grinding process can be used to grind the particles to the preferred diameter sizes in the range between about 10 ⁇ m to 180 ⁇ m.
  • the preferred low shear grinding method uses a one or more stage, two roll mill such as a crackulizer manufactured by Modern Process Equipment. The gap between the rollers is reduced for each stage of the grinding process so that the size of the particles become gradually smaller as they sequentially progress through the stages. The final average particle size will depend on the feed rate, input particle size, hardness of the particles, rotation speed and the gap settings.
  • the particle size can be measured using a conventional sieving machine or an ultrasonic sieving machine. This low shear grinding process does not disrupt the zeolite-binder bonds and produces a high yield of particles in the preferred size range.
  • the commercial zeolites have been shown to have potentially large adsorption capacities and a high specificity for lead and other toxic heavy metals.
  • adsorption isotherm data shows that zeolites with 3A structure have poor adsorption for lead, the 4A and 5A zeolite crystals have high adsorption capacity and specificity for lead.
  • the present inventors have discovered that when 4A and 5A zeolites, whose sizes are in the 1 to 3 ⁇ m range, are agglomerated, calcined and ground using a low shear process, they are especially suitable to the removal of lead as is shown below.
  • a 100 ppm lead solution was made in a 2 liter glass volumetric flask by diluting 0.0622 grams of lead nitrate with sufficient deionized water to make 2 liters of solution. The flask was agitated to assure a homogenous solution. The pH of the solution was approximately 7, and the solution temperature was kept at room temperature at approximately 68-72°F. The solution was stored in a dark storage area to prevent photochemical degradation.
  • the agglomerated zeolite material was a non-commercial product obtained from PQ Corporation.
  • the starting zeolite was 4 A molecular sieve material, which was agglomerated by mixing with bentonite clay.
  • Particle size after agglomeration and prior to grinding was 8 x 30 mesh. Small samples were ground my hand using a laboratory mortar and pestle. The particles were crushed using an up and down motion to avoid excess shear. Particle size after grinding was approximately -200 mesh or less than 75 ⁇ m.
  • Table 1 below shows the lead solution concentration vs. time for the zeolite ion exchange material prepared and measured according to examples 1 , 2 and 3.
  • Comparative examples 9 and 10 are results from ion exchange material Alusil 70® sold by Selecto Scientific, Inc., and comparative example 1 1 was the result using the ion exchange material ATS® from Englehard Corporation. They are both based on gel technology and are manufactured with gel sizes averaging 30 to 50 ⁇ m. They are commonly incorporated into carbon block filters for household lead removal applications. The procedure in example 3 was used in obtaining the data in comparative examples 9 to 11.
  • the superiority of the zeolite ion exchange material is shown by comparing examples 4-8 with examples 9-11.
  • the zeolite ion exchange material shows improved kinetics by the faster decrease in lead concentration.
  • the zeolite material, according to the present invention reduced the lead concentration to an average of less than 300 ppb in 30 minutes, while the commercial ion exchange materials only reduced lead concentrations to an average of about 5400 ppb in 30 minutes.
  • this unique zeolite material has an improved adsorption capacity and equilibrium for lead than the commercial lead removal products.
  • the zeolite material consistently reduced the lead concentration during extended contact times to less than 50 ppm, while the commercial ion exchange materials had difficulty reducing the lead level to less than 200 ppm.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Water Treatment By Sorption (AREA)

Abstract

La présente invention concerne la production de composites particulaires de zéolithe dont les particules présentent des diamètres moyens compris dans un intervalle allant d'environ 10 νm à environ 180 νm. Ces grandeurs de diamètres conviennent particulièrement à une utilisation conjointe avec des filtres blocs à charbon utilisés dans les applications domestiques d'eau potable. Les particules de composite sont produites par mélange de zéolithe commerciale de 4 à 5 Å à de l'eau et à des liants organiques ou inorganiques, avec pour résultat une structure stable dans l'eau. Les particules sont alors broyées dans un broyeur à faible cisaillement, sous un contrôle extrêmement précis, afin de produire, avec un rendement élevé, des particules qui conviennent à l'emploi dans des épurateurs blocs à charbon et dans d'autres éléments de filtres composites.
PCT/US1999/015022 1998-07-07 1999-07-02 Composite a base de zeolithe de petit diametre, stable a l'eau, utile comme materiau echangeur d'ions WO2000001459A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US11102898A 1998-07-07 1998-07-07
US09/111,028 1998-07-07

Publications (1)

Publication Number Publication Date
WO2000001459A1 true WO2000001459A1 (fr) 2000-01-13

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Application Number Title Priority Date Filing Date
PCT/US1999/015022 WO2000001459A1 (fr) 1998-07-07 1999-07-02 Composite a base de zeolithe de petit diametre, stable a l'eau, utile comme materiau echangeur d'ions

Country Status (1)

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WO (1) WO2000001459A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002048043A2 (fr) * 2000-12-14 2002-06-20 Engelhard Corporation Adoucisseur poreux d'eau statique contenant une composition hybride de zeolite-silicate
WO2003008339A1 (fr) * 2001-07-13 2003-01-30 Novoktan Gmbh Mineralöl-Additive Procede
CN102519852A (zh) * 2011-11-21 2012-06-27 浙江大学 裂隙-岩块间水交换试验装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4613578A (en) * 1984-06-20 1986-09-23 Pq Corporation Porous zeolite granules stable in aqueous solutions
US4746439A (en) * 1987-05-15 1988-05-24 Manville Corporation Process for removal of heavy metal contamination in waste water
US5053139A (en) * 1990-12-04 1991-10-01 Engelhard Corporation Removal of heavy metals, especially lead, from aqueous systems containing competing ions utilizing amorphous tin and titanium silicates
US5071804A (en) * 1988-09-08 1991-12-10 Engelhard Corporation Ion-exchange agent and use thereof in extracting heavy metals from aqueous solutions
US5286464A (en) * 1993-06-14 1994-02-15 Nalco Chemical Company Silica gel ion exchange resins for the selective removal of lead and cadmium ions from aqueous liquids

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4613578A (en) * 1984-06-20 1986-09-23 Pq Corporation Porous zeolite granules stable in aqueous solutions
US4746439A (en) * 1987-05-15 1988-05-24 Manville Corporation Process for removal of heavy metal contamination in waste water
US5071804A (en) * 1988-09-08 1991-12-10 Engelhard Corporation Ion-exchange agent and use thereof in extracting heavy metals from aqueous solutions
US5053139A (en) * 1990-12-04 1991-10-01 Engelhard Corporation Removal of heavy metals, especially lead, from aqueous systems containing competing ions utilizing amorphous tin and titanium silicates
US5286464A (en) * 1993-06-14 1994-02-15 Nalco Chemical Company Silica gel ion exchange resins for the selective removal of lead and cadmium ions from aqueous liquids

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002048043A2 (fr) * 2000-12-14 2002-06-20 Engelhard Corporation Adoucisseur poreux d'eau statique contenant une composition hybride de zeolite-silicate
WO2002048043A3 (fr) * 2000-12-14 2003-12-18 Engelhard Corp Adoucisseur poreux d'eau statique contenant une composition hybride de zeolite-silicate
WO2003008339A1 (fr) * 2001-07-13 2003-01-30 Novoktan Gmbh Mineralöl-Additive Procede
CN102519852A (zh) * 2011-11-21 2012-06-27 浙江大学 裂隙-岩块间水交换试验装置
CN102519852B (zh) * 2011-11-21 2013-10-30 浙江大学 裂隙-岩块间水交换试验装置

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