HU191047B - Process for production of chemically treated granulated adsorbents - Google Patents

Abstract

A process is claimed for the prepn. of chemically treated granular adsorbents. The method involves (a) classifying a granular mixt. of (i) 50-80 wt.% Ti and/or Zr cpds., and/or zeolites and (ii) 20-50 wt.% of amorphous Al2O3 of 2-50 microns and 0.2-5 mm grains of inert Al2O3, and boehmite-contg. material; (b) treating the granulate with acid (esp. conc. H2SO4) and/or an organic material (esp. melamine), to render it porous; and (c) chemically surface-treating the granules to deposit on them 1-10 wt.% ferric hydroxide and/or treating them with Ca and Mg cpds.

Description

The present invention relates to a process for the production of particulate chemically treated adsorbents which are suitable for the selective removal of many contaminants in environmental protection, especially in water purification.

Adsorption processes play an important role in environmental research and in the removal of toxic elements that contaminate air and water. Adsorbents are used in a wide variety of sectors within the chemical industry and are known for many processes.

Inorganic-based adsorbents used in adsorption water purification processes are described in Vesely, V., Pekárek, V., Talanta Review I, 19, 219-262, 1972, II, 19, 1245-1283. 1972, a publication which deals in detail with the production of adsorbent materials, their properties and their applications.

Granulated activated carbon has been widely used as an adsorbent in drinking water purification for several decades. They mainly remove organic humic substances and contaminants that influence the smell and taste of water in properly designed and constructed adsorbers. Exhausted adsorbents can be regenerated and reused.

The Hg (II) content of natural waters can be effectively removed by adsorption on MnO ₂ (Lockwood, RA, Chen, KY: Environmetal Science and Technology 7 (11), 1028. 1973). It was found that adsorption at pH 6-8 is characterized by Freundlich isotherm and that MnO _{2 is} capable of removing Hg (II) either naturally or in water treatment.

Amorphous iron (III) oxide hydroxide (gallite) has been used to adsorb copper and lead ions from water in the United States (KC Swallow, DH Hume, F. M. More: Environmental Science and Technology, 14 (II) 1223. 1980). It was found that the adsorption effect is based on the law of mass effect. The adsorbent was prepared by mixing stoichiometric amounts of carbonate-free solutions of NaOH and Fe (NO ₃ ) ₃ . The resulting solution was used to prepare adsorption isotherms.

The alumina adsorbent of 210 m ² / g, manufactured by the American Aluminum Company, was used by Neufeld et al. To remove orthophosphates from water (D. Neufeld, G. Thodos, Environmental Science and Technology, 3 (7) 661, 1969). The adsorption process was characterized by a Langmuir-type isotherm.

Mixed phosphates were removed from the wastewater by three activated alumina of different grades and specific surfaces (W. C. Yee, J. Amer. Water Works Assoc., 58 (2) 239, 1966). In addition to static experiments, laboratory and semi-industrial dynamic experiments were also performed. The differently activated alumina is widely used in many water purification processes. Methods for removing fluoride and arsenate ions have also been developed in drinking water treatment. Savinelli et al. Have used activated carbon, hydroxylapatite, magnesium, finely ground bone, natural and synthetic ion exchangers and activated alumina in fluoride removal adsorbent columns (F.A. Savinelli, A.P. Black, J.

Amer. Water Works Assoc., 50 (1) 33. 1958). As regards the mechanism of fluoride ion removal by alumina treated with aluminum sulphate, it has been found that an ion exchange takes place.

A 90% purification efficiency has been achieved by US researchers in removing the arsenic content of water containing 0.06 mg / l of arsenic after treatment with an alumina-filled adsorbent column (E. Bellack, J. Amer. Water Works Assoc., 63, 454, 1971). .

Also known are adsorbents for the preparation of titanium compounds and / or zirconium compounds and / or zeolites in an amount of 50-80% w / w, 20-50% w / w of X-ray amorphous alumina, γ-alumina and 2-50 μτη. The granulate thus obtained is made porous by treatment with acidic, preferably concentrated, sulfuric acid and / or volatile organic material, preferably melamine.

The described methods utilized laboratory-prepared precipitates of various chemical compositions, or commercially available adsorbents, to remove contaminants of water.

The adsorbents described herein are of limited utility for removing arsenic from water because of their low adsorption capacity for arsenic. The disadvantage of using iron (III) hydroxide coagulant used in coagulation processes is that large amounts of toxic sludge are produced during purification and must be disposed of.

It is an object of the present invention to provide a process for preparing inorganic-based adsorbents for use in environmental protection, particularly water purification. The adsorbents thus prepared may be selectively removed from water contaminating components, and the adsorbents are resistant to the water to be purified and, moreover, long-lasting and therefore economical to use.

The invention thus provides a process for the preparation of particulate chemically treated adsorbents.

The inert core produced by the process known in the art and having a particle size of 0.2-5.0 mm, containing 20-50% w / w of X-ray amorphous alumina, γ-alumina and / or boehmite, is preferably granulated with the active components. 80% w / w of titanium compounds and / or zirconium compounds and / or zeolites and granules thus obtained are rendered porous by treatment with acidic, preferably concentrated sulfuric acid and / or volatile organic material, preferably melamine, according to the invention. preferably by applying 1- (10% w / w) relative amount of ferric hydroxide relative to the iron content by direct precipitation of the surface of the particles or by treating the surface of the particles with the calcium-magnesium ionic form by treatment with calcium and magnesium compounds.

Preferably, according to the invention, the iron (III) hydroxide is separated from the iron (III) chloride with ammonium hydroxide on the surface of the particles.

Finally, according to the invention, the surface of the particles is in the calcium and magnesium ion forms

Calcium chloride and magnesium chloride are preferably used for the conversion of 191,047.

In our experiments, it has been found that the adsorbents having the most favorable adsorption properties can be prepared by using a particle size of 0.2-5 mm for the raw materials used as inert cores, because in this case the hydrodynamic resistance of the adsorbents produced is appropriate. During the nucleation process, the inner layers of the adsorbents are first formed from inert materials and then granulated using the active components. The surface of granules prepared in known manner is chemically treated.

The porosity of the layer applied to the inert core is determined by the composition of the materials used as the active components. Depending on the porosity of the granules required to form the chemically treated adsorbent, the active components may be combinations of titanium compounds or zirconium compounds or zeolites with the listed active components.

The invention is illustrated in detail by the following non-limiting examples.

Example I

(a) Granulation

4.5 kg of titanium oxide hydrate having a stoichiometric composition of TiO (OH) _{2 with a} moisture content of 55% w / w and

A homogeneous mass is prepared from 1.5 kg of alumina using a laboratory kneading machine and dispersed through a 1.0 mm sieve. The wet pellets were dried at 105 ° C for one hour and then stored at 700 ° C for one hour in an oven.

Oxidic composition of the granulate:

TiO ₂ = 52.4% w / w, Al ₂ O ₃ = 47.6% w / w

(b) Treatment with sulfuric acid

The heated and cooled pellets are poured into 96% sulfuric acid with vigorous stirring and cooling. During acidification, the temperature of the solution is below 60'C. After 20-25 minutes, the sulfuric acid was decanted and the water washed with anhydrous and dried (105 ° C, 2 hours).

(c) Chemical treatment

1 kg of the dried granulate is mixed in a vacuum desiccator with a volume of 1.2 dm ³ of 20% w / w FeCl 3 solution. Using a water jet pump or a vacuum pump, a vacuum of Δρ ≤ 10 ^J Pa is created in the desiccator and maintained until all the air between the particles has been completely removed. The excess FeCl3 solution, which was not retained by the granule layer, was then removed and then, under vigorous stirring and cooling, cc. NH ₄ 0H was used to prepare an iron (III) hydroxide layer. The adsorbent thus prepared is dried at room temperature.

Chemically treated, particulate adsorbent can be widely used in water purification, for example to remove toxic arsenic in drinking water.

The adsorbent mass weighed 100 g, 1.00 cm ³ volume Erlenmeyer flask equipped with a ground glass stopper. 100 cm ³ of a solution are poured onto the adsorbent, which contains 1,356 mmol / dm ³ As (III) ions, and 1.311 mmol / dm ³ As (V) ions. The flask was shaken for 18 hours with a Shaker Bath (609 / A, MTA Kutesz). From the solution, the adsorbent adsorbs 109.0 pmoles of As (V) and 115.57 pmoles of ions A, (III).

For comparison, we also performed counterweight experiments with A1 ₂ O ₃ adsorbent. 100 cm ³ of a solution is poured 1.00 g adsorbent containing 1.36 mmol / dm ³ As (III) ions and 1.29 mmol / dm ³ As (V) ions. After 18 hours of shaking, the adsorbent adsorbed 70.88 pmoles of As (III) and 84.0 pmoles of AS (V).

Example 2

(a) Core formation From a titanium oxide hydrate containing 55% w / w of water and 1 kg of special alumina, a homogeneous mass is made in a laboratory kneading machine and molded into a cylindrical particle of 3 mm diameter and 3 10 mm length by extruder. The extrudate was dried at 105 ° C to a moisture content of 10% w / w and dispersed in a laboratory oscillating granulator using a 1 mm mesh insert.

The granule cores thus prepared are less than 1 mm in size and are predominantly 0.2-0.8 mm in weight. Oxidic composition:

TiO ₂ = 52.4% w / w; A1 ₂ O ₃ = 47.6% w / w.

b) Enlarging A homogeneous powder mixture containing 30% w / w alum and 70% w / w titanium dioxide (anatase) is prepared and this amount is

Layered on cores produced in the manner described in a) according to the following technology:

For dry matter, a pellet core of 2.35 kg in weight is placed in a 0.7 m diameter, 0.5 m deep truncated-conical-cylindrical rotary drum. Drum speed 30 min axis 0 Water is sprayed onto the particles in intense motion using a pneumatic atomizer and powder is added through a vibrating screen. The moistening and powder addition are alternately repeated until the 3 kg powder mixture is introduced. The fluid delivery rate is approx. 30 cm ³ / min, the average droplet size produced by the nebulizer is approx. 40 pm. The wetting is carried out until the granules are just beginning to agglomerate. The relative volume of water per unit weight of the gate is 0.3 dm ³ / kg. The powder feed rate is 0.1 kg / min. 0.5 kg of powder and 0.15 dm ^{3 of} water were used to apply one meadow.

After the last dose of powder was applied, the granules were wet-rolled for an additional 15 minutes.

(c) Heat treatment

The pellets obtained in (a) and (b) are placed in an airtight autoclave and the temperature is adjusted to 130 ° C and maintained at this temperature for 16 hours.

191,047

After cooling the autoclave, the granules are removed, dried in an oven at 105 ° C for 1 hour, and then stored at 700 ° C for 1 hour in an oven. The particle size thus produced (0.4-1.25 mm).

(d) Chemical treatment

The chemical treatment is carried out as described in Example 1 (c).

The chemically-treated, pelletized adsorbent mass weighed 100 g, 1.00 cm ³ volume Erlenmeyer flask equipped with a ground glass stopper. The adsorbent was poured into 100 cm ^{3 of} a solution containing 1.383 mmol / dm ³ As (V) and 1.292 mmol / dm ³ As (III) ions. The flask is shaken for 18 hours with a Shaker Bath (609 / A MTA Kutesz). From the solution, the adsorbent binds 62.92 μτηόΐ As (V) and 79.50 pmoles of As (III) ions.

Example 4

granulation

A homogeneous mass is made from 1.2 kg of zirconia and 0.3 kg of special alumina by the addition of 0.3 kg of water in a laboratory kneading machine. This is dispersed through a 1.0 mm sieve. The granules are dried at 105 ° C (1 hour) and then annealed at 700 ° C (1 hour). The granules are chemically treated as described in Example 1 (c).

From granulated and chemically treated adsorbent

102.4 g are weighed into a 3.2 x 15 cm adsorbent column. The adsorbent has a pH of 7.2 to 7.3 at an average bed flow rate of 15 bed volumes / h

A solution of 3.94 mg of As / dm ³ was passed through a solution of 89.6 dm ³ . The adsorbent absorbs 96.07% of the arsenic ions.

Example 3

(a) Nuclear training

A homogeneous powder mixture was prepared from 4.0 kg titanium dioxide (anatase) powder and 1.71 kg alumina. This powder mixture containing 70% w / w alumina and 30% w / w titanium dioxide is kneaded in a laboratory kneading machine by gradual addition of 2.2 dm ^{3 of} water (moisture content: 0.39 dm ^{3 of} water / kg dry matter). The paste is then used to form granule cores as described in Example 1 (a) (puncture through sieving, drying, dispersion).

b) Enlargement

The mm fraction (0.4-1.0) mm of granule cores was sieved (3 kg) and, as described in Example 2 (b), was subjected to 3 kg, 70% w / w alum and 30% w / w titanium. a powder mixture containing dioxide (anatase) is deposited. The relative amount of water required for wetting is 0.45 dm ³ / kg powder.

The particle size distribution of the granules thus produced is as follows:

sieve size (mm) relative weight (%)

(0.4-0.6) 19 (0.6-0.8) 40 (0.8-1.0) 32 (1.0-1.25) 9 altogether 100

The heat treatment of the granules is carried out as in Example 2 (c) and the granulation is treated as in Example 1 (c).

The adsorbent mass weighed 100 g, 1.00 cm ³ volume Erlenmeyer flask equipped with a ground glass stopper. 100 cm ³ of a solution are poured onto the adsorbent, containing 0.706 mmol / dm ³ As (V) and 0.669 mmol / dm ³ As (III) ions. The flask is shaken for 18 hours with a Shaker Bath (609 / A MTA Kutesz). From the solution, the adsorbent adsorbs 43.92 pmoles of As (V) and 52.37 gmoles of As (III) ions.

Example 5

Chemical treatment of the granules prepared as described in Example 3 (a) and (b) was carried out as follows:

After the concentrated sulfuric acid treatment described in Example 1, a mass of 82.5 g of the neutral-washed adsorbent dried at 105 ° C was loaded onto a 3.2 x 15 cm adsorbent column with 10 bed volumes of 700 mg Ca / dm ³ and 500 mg / kg. The solution is converted to Ca and Mg ion forms with a solution of dm ³ at a flow rate of 5 bed volumes / h. The adsorbent is then washed with 5 bed volumes of distilled water. To this adsorbent was added a solution of 71.2 dm ³ , with an average concentration of 10.08 mg P / dm ³ , pH 6.75, at a flow rate of 5 bed volumes / h. The concentration of the phosphorus ion in the effluent during depletion is below the concentration limit of 1 mg P / dm ³ and the adsorbent absorbs 90.3% of the phosphorus.

If the adsorbent column is filled with the same volume (80 cm ³ ) of Al ₂ O ₃ adsorbent (88.2 g), the adsorbent will have a phosphorus content of 71.2 dm ³ after passing through an average of 10.08 mg P / db ³ solution. , Adsorbing 6%.

Example 6

a) Nucleation kg of special alumina is placed in a rotating ellipsoidal rotary drum 1.2 m in diameter and 0.6 m deep, and the drum is rotated at 35 min- ¹ . Water was sprayed onto the swirl layer at a rate of 20 ml / ml using two fluid atomisers (spray air flow rate: 400 dm ³ / h; pressure:

3-10 * Pa). The granulate fraction of 0.8-1.0 mm is sieved out of the resulting granulate,

b) Enlargement

Mm cores prepared above, 3 0.8-1.0 kg and is inserted into the rotating drum (speed: 45 mm ¹⁾ while moving the cores intehzív alternating layers of swirling water and sprayed powder coating is added. The coating powder has a total composition of 4191,047 horse parts alumina and 10 parts TiO ₂ . Wetting and powdering were continued until a particle size of 1.0-1.25 mm was reached. The added powder weighs 3 kg.

c) The pellets prepared in (b) are placed in an airtight autoclave and the temperature is adjusted to 130 ° C for 16 hours. The granules were removed from the autoclave and dried at 105 ° C for 1 hour.

(d) Chemical treatment

The chemical treatment is carried out as in Example 1 (c). The adsorbent mass weighed 100 g, 1.00 cm ³ volume Erlenmeyer flask equipped with a ground glass stopper. 100 cm ³ of a solution are poured onto the adsorbent, which contains 669.5 pmol / dm ³ As (III) and 629.1 pmol / dm ³ As (V) ions. The flask was shaken for 18 hours with a Shaker Bath (609 / A MTA Kutesz). From the solution, the absorbent adsorbs 61.9 pmoles of As (III) and 60.35 pmoles of As (V) ions.

Summary of equilibrium experiments

Example

Sign of adsorbent

Equilibrium Adsorbed Concentration Material mmole / dm ³ μιηόΐ / g

As (III) As (V) As (III) As (V)

First Ti Al (50-50) T'e (OH) 1,356 1,311 115.57 109.0 A1 ₂ O ₃ 1.36 1.29 60.88 64.0 Second Ti Al (70-30) Fe (OH) j 1,292 1.387 79.50 62.92 Third Ti-Al (30-70) -Fe (OH) ₃ 0.669 0.706 52.37 43.92 6th Ti-Al (66-33) -Fe (OH) ₃ 0.669 0.629 61.90 60.35 7th Ti-Al (60-30) -Fe (OH) ₃ 1.31 1.35 84.22 91.71

Exhaustion experiments Example Sign of adsorbent Volume treated (dm ³ ) Average Removal Conc. (mg / efficacy ³ ) ka (%) 5 Ti-Al (3O-7O) Ca, Mg Al ₂ O ₃ 71.2 71.2 10.08 90.3 10.08 85.6

Example 7

(a) Nuclear training

In preparing the adsorbent, nucleation is a

Example 3 (a).

b) Increasing the size to kg of 0.8-1.0 mm cores by applying the layering technique described in Example 3 (b) to 3 kg of coating powder having the following composition:

- 60% w / w TiO ₂ pigment (anatase),

- 30 m / m% of special alumina,

10% w / w melamine (2,4,6-triamino-s-triazine) having a particle size of 10-20 pmoles.

(c) Heat treatment

The melamine-containing pellets produced are heat-treated at 130 ° C in a sealed autoclave for 16 hours and then stored in an oven at 500 ° C for 2 hours. As a result of the glow, the melamine is completely removed from the granules, resulting in high secondary porosity.

(d) Chemical treatment

The chemical treatment was carried out as in Example 1 (c).

The adsorbent mass weighed 100 g, 1.00 cm ³ volume Erlenmeyer flask equipped with a ground glass stopper. 100 cm ³ of a solution are poured onto the adsorbent, which contains 1.31 mmol / dm ³ As (III) and 1.35 mmol / dm ³ As (V) ions. The flask was shaken for 18 hours with a Shaker Bath (609 / A MTA Kutesz). From the solution, the adsorbent adsorbs 84.22 pmoles of As (III) and 91.71 pmoles of As (V) ions.

Claims (3)

Claims I. Process for the preparation of particulate chemically treated adsorbents, wherein the active ingredient is preferably 50-80% w / w of titanium compounds and / or zirconium compounds and / or zeolites with ₃₀ needles, 20-50% w / w, in the range of 2-50 μηι. starting from an inert core particle size between 0.2-5 mm with X-ray amorphous alumina, γ-alumina and boehmite granulated and the so produced granules are placed in a lake ₃₅ management and / or volatile organic compound, preferably melamine, porous acid, preferably concentrated sulfuric characterized in that the surface of the porous particles is chemically treated, so that the vastar _4Q content text applying hydroxide is preferably 1-10% w / w amount of iron (III) direct precipitation as a second layer surface of the particles on, or the surface of the particles is converted to calcium-magnesium ionic calcium and magnesium compounds treatment. 2. A method according to claim 1 is characterized ^& ve to a hydroxide of iron (III) is separated from the surface of the particles of iron (III) chloride just ammonium hydroxide. 3. A method according to claim 1 characterized in that using calcium chloride and magnesium chloride to convert the surface of the particles of calcium and magnesium in ⁵⁰ magnesium ionic forms.