JP2016107257A - Adsorbing agent and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adsorbing agent suitably used for adsorption and removal of strontium contained in water.SOLUTION: There is provided a strontium-adsorbing agent which contains a barium containing aluminosilicate and exhibits a Na-A type zeolite-like diffraction pattern in which diffraction peaks are observed in at least 29.8 or more and 30.2° or less, 23.8° or more and 24.2° or less and 7.0° or more and 7.4° or less by a powder X-ray diffraction method. The content of BaO in the aluminosilicate preferably is 2 mass% or more and 38 mass% or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an adsorbent suitably used for adsorption removal of strontium contained in water and a method for producing the same.

As a method for treating a waste liquid containing a radioactive substance, a treatment method for adsorbing and removing a radionuclide with an inorganic adsorbent, an ion exchange resin, or the like is known. As an adsorption method using an inorganic adsorbent, for example, the following method is known.
(1) A method using a titanium silicate compound, titanic acid, titanate, and a zeolite compound (Patent Document 1 below).
(2) A method using manganese dioxide as an adsorbent (Patent Document 2 below).

Regarding the removal of strontium, the following methods are known.
(1) A method of removing an aqueous solution containing strontium by bringing it into contact with a perovskite type compound containing titanium or niobium (Patent Document 3 below).
(2) A method of removing radioactive strontium from a waste liquid using a solid material in which any one of calcium carbonate, strontium carbonate, and barium carbonate is occluded (Patent Document 4 below).
(3) A method of adsorbing strontium contained in seawater using A-type zeolite or X-type zeolite encapsulated with a calcium alginate membrane (Patent Document 5 below).

JP 2014-029269 A Japanese Patent Laid-Open No. 4-86599 JP 2005-230664 A Japanese Patent Laid-Open No. 2002-267996 JP 2013-174578 A

  However, the seawater contains much more cognate ions (calcium and magnesium) than strontium. Therefore, in the conventional technology, it is difficult to efficiently separate and adsorb strontium from seawater due to the influence of coexisting calcium and magnesium.

  An object of the present invention is to provide a strontium adsorbent and a method for producing the same, which can eliminate the various disadvantages of the above-described prior art.

  The present invention is a strontium adsorbent comprising an aluminosilicate containing barium, which is at least 29.8 ° to 30.2 °, 23.8 ° to 24.2 ° by powder X-ray diffraction, and The present invention provides a strontium adsorbent exhibiting a Na-A type zeolite-like diffraction pattern in which a diffraction peak is observed at 7.0 ° to 7.4 °.

The present invention also provides a method for producing the adsorbent as described above.
A step of mixing Na-A type zeolite and a barium-containing aqueous solution to ion-exchange sodium in Na-A type zeolite with barium;
Wherein in the step, it becomes Na-A type zeolite and 30% by weight or less proportion than 3 wt% of Na-A type zeolite occupied in the mixed liquid after mixing with the barium-containing solution, and, BaO / Na ₂ The present invention provides a method for producing a strontium adsorbent, wherein Na-A zeolite and the barium-containing aqueous solution are mixed at a mixing ratio such that the molar ratio of O is 0.04 or more and 1.5 or less.

Furthermore, the present invention provides another preferred method for producing the adsorbent,
A silicon source, an aluminum source, a barium source, an alkali source, and water are mixed so that a mixed liquid having a composition represented by the molar ratio shown below is obtained. The present invention provides a method for producing a strontium adsorbent, which includes a step of aging under heating at a temperature not higher than ° C.
SiO ₂ / Al ₂ O ₃ is 1.8 or more and 2.2 or less Na ₂ O / SiO ₂ is 2.0 or more and 3.0 or less A-type zeolite Na ₂ O · Al ₂ O converted from the amount of Al ₂ O ₃ charged ₃ · 2SiO ₂ · 4.5H ₂ BaO against Na ₂ O, which is calculated from the O ratio BaO / Na ₂ O is 0.04 to 1.5

Furthermore, the present invention provides another preferred method for producing the adsorbent,
Provided is a method for producing a strontium adsorbent, comprising mixing a granular material containing Na-A zeolite and a barium-containing aqueous solution to ion-exchange sodium in the granular material containing Na-A zeolite with barium. Is.

  According to the present invention, an adsorbent capable of selectively adsorbing and removing strontium contained in water without being affected by coexisting species such as calcium is provided. According to the present invention, an aluminosilicate effective as the adsorbent can be produced by an industrially advantageous method.

FIG. 1 is an XRD diffractogram of Na-A type zeolite used as a raw material in Example 1, and an XRD diffractogram measured before and after subjecting the adsorbent obtained in Example 1 to adsorption of strontium. FIG. 2 is an XRD diffractogram of the adsorbents obtained in Examples 6-8. FIG. 3 is an XRD diffractogram of the granular material containing Na-A type zeolite used as a raw material in Example 11, and an XRD diffractogram of the adsorbent obtained in the same example.

  The adsorbent of the present invention contains an aluminosilicate containing barium (hereinafter also simply referred to as aluminosilicate). The adsorptive capacity of the adsorbent of the present invention is mainly derived from this aluminosilicate. The aluminosilicate is mainly a barium salt, but may contain a salt of another metal such as an alkali metal such as sodium or potassium in addition to barium.

The aluminosilicate contained in the adsorbent of the present invention is generally represented by wA ₂ O.xBaO.yAl ₂ O ₃ .zSiO ₂ .nH ₂ O. Here, A represents Na and K, x, y, and z represent numbers greater than 0, and n represents a number greater than or equal to 0. w represents a number of 0 or more, but is usually a number greater than 0. The aluminosilicate contained in the adsorbent of the present invention is at least 29.8 ° or more and 30.2 ° or less, 23.8 ° or more and 24.2 ° or less when measured by powder X-ray diffraction method, and It exhibits a Na-A zeolite-like diffraction pattern in which a diffraction peak is observed at 7.0 ° to 7.4 °. “Na-A-type zeolite-like diffraction pattern” does not show the same diffraction pattern as Na-A-type zeolite, which is a highly crystalline substance, but only the appearance angle of the diffraction peak except for the high and low crystallinity. When attention is paid, it means that the diffraction peak is observed at the same angle as the appearance angle of the diffraction peak of the Na-A type zeolite. Therefore, when the Na-A type zeolite is measured by the powder X-ray diffraction method, diffraction peaks are observed in at least the above three angle ranges. These three angle ranges correspond to the angle range of the peak with the highest intensity in the Na-A type zeolite followed by the two peaks with the highest intensity. Table Note that the Na-A type zeolite, a kind of synthetic zeolite, in the general formula _{Na 2 O · Al 2 O 3} · 2SiO 2 · pH 2 O ( Here, p is 0 to 4.5.) Is done. Thus, the aluminosilicate according to the present invention exhibiting a Na-A-type zeolite-like diffraction pattern is considered to have a Na-A-type zeolite-like crystal structure in at least a part of its structure.

  The measurement conditions of the above-mentioned powder X-ray diffraction method can be set as follows, for example. In other words, the device name: D8 AdvanceS and the manufacturer: Bruker are used as measuring instruments. The target Cu, the source Cu-Kα, the tube voltage 40 kV, the tube current 40 mA, the scanning speed 0.1 ° / sec, and the reading width 0.02 °.

The aluminosilicate contained in the adsorbent of the present invention has a range of 10.0 ° to 10.6 ° in addition to the above three ranges when measured by a powder X-ray diffraction method (hereinafter referred to as “fourth”). In addition to the fourth range, it is more preferable that a diffraction peak is also observed in the range of 12.4 ° to 12.8 °. . Specifically, it is particularly preferable that the aluminosilicate contained in the adsorbent of the present invention has a diffraction pattern shown in Table A below when measured by a powder X-ray diffraction method. The relative intensity (I / Io) below is the angle of appearance of the highest intensity peak in Na-A type zeolite (2θ = 7.2).
) Shows the ratio to the intensity (Io) of the diffraction peak appearing at the same angle. The intensity ratio here is measured as a ratio of peak heights. The peak height is obtained from the diffraction peak pattern as follows. First, a straight line is obtained by connecting two bottom points of one peak. Then, a perpendicular line is drawn from the peak apex to intersect with the straight line, and the distance between the obtained intersection and the peak apex is defined as the peak height.

  In order to obtain an aluminosilicate in which a diffraction peak is observed in the above range as measured by a powder X-ray diffraction method, the adsorbent of the present invention is a method (A) or (B) described later, and further described later ( What is necessary is just to manufacture by the method of C). Since the aluminosilicate used in the present invention has a diffraction peak observed in the specific range as measured by the powder X-ray diffraction method as described above, the adsorbent of the present invention containing this aluminosilicate is naturally powder X. A diffraction peak is observed in the specific range as measured by the line diffraction method.

The reason why the adsorbent of the present invention using the aluminosilicate having barium-containing aluminosilicate as described above has a high adsorption performance of strontium as described above is as follows. I guess. When the aluminosilicate containing barium comes into contact with seawater, the barium reacts with sulfate ions in the seawater, so that barium sulfate is generated and deposited on the surface of the Na-A type zeolite-like structure of the aluminosilicate. . Then, strontium ions are selectively adsorbed and removed from the seawater by selectively adsorbing strontium ions in the voids from which barium ions are removed from the zeolite-like structure. In the adsorbent of the present invention, the aluminosilicate contained therein has a zeolite-like diffraction pattern as described above, but usually does not have as high crystallinity as Na-A type zeolite. Therefore, in the vicinity of the surface of the crystal skeleton in the adsorbent of the present invention, there is a large amount of Ba ²⁺ that is not taken into the crystal skeleton and can be exchanged with strontium ions. For this reason, the present inventors ^{presume that} the adsorbent of the present invention has high Sr ²⁺ adsorption performance. As described in Example 1 described later, according to X-ray diffraction analysis, the adsorbent of the present invention exhibits a barium sulfate crystal peak after strontium adsorption, which supports the aforementioned adsorption mechanism.

  In the adsorbent of the present invention, the BaO content in the aluminosilicate constituting the adsorbent is preferably 2% by mass or more and 38% by mass or less. By setting the BaO content to 2% by mass or more, the adsorption amount of strontium can be further increased. Moreover, the manufacturing cost of the adsorption agent of this invention can be reduced by setting it as 38 mass% or less. For example, when the adsorbent of the present invention is produced by ion exchange described later, in order to make the BaO content in the aluminosilicate more than 38% by mass, ion exchange must be performed a plurality of times, for example, three times or more. However, it is industrially disadvantageous in terms of time, labor, and drug costs. From these viewpoints, the BaO content in the aluminosilicate is more preferably 10% by mass to 38% by mass, further preferably 20% by mass to 38% by mass, and more preferably 25% by mass to 38%. It is still more preferable that it is less than mass%, and it is most preferable that it is 27 mass% or more and 38 mass% or less. The BaO content of the aluminosilicate is measured by fluorescent X-ray analysis, specifically by the method of the examples described later. In order to produce an aluminosilicate having such a BaO content, the amount of Ba used is adjusted in the production of the adsorbent of the present invention by the production method (A), (B) or (C) described later. do it.

The theoretical maximum value of the BaO content in the aluminosilicate is w: x: y when the composition of the aluminosilicate is the above general formula “wA ₂ O.xBaO.yAl ₂ O ₃ .zSiO ₂ .nH ₂ O”. : The BaO content when z: n is 0: 1: 1: 2: 0. Therefore, the theoretical maximum value of the BaO content is calculated to be 40.8% by mass. Moreover, as a preferable range of BaO content rate in the adsorbent of this invention, the range similar to the numerical range quoted above as a preferable range of BaO content rate in aluminosilicate is mentioned.

The aluminosilicate contained in the adsorbent of the present invention preferably reflects a Na-A type zeolite-like crystal peak, and preferably has a SiO ₂ content of 27 mass% to 37 mass%, particularly preferably. Is 29% by mass or more and 35% by mass or less, and the Al ₂ O ₃ content is 24% by mass or more and 36% by mass or less, and particularly preferably 26% by mass or more and 34% by mass or less. The content of SiO ₂ and Al ₂ O _{3 in} the aluminosilicate is measured by fluorescent X-ray analysis, specifically by the method of the examples described later.

The adsorbent of the present invention may contain an alkali metal salt such as sodium or potassium as described above, and the A ₂ O content of the aluminosilicate contained in the adsorbent (A is Na and K). Is preferably 17% by mass or less, more preferably 16.5% by mass or less, still more preferably 15% by mass or less, and particularly preferably 13% by mass or less. For example, when a sodium compound is exclusively used as the alkali metal compound in the production of the adsorbent of the present invention, the Na ₂ O content of the aluminosilicate contained in the adsorbent of the present invention is the same as the above A ₂ O content. It is preferable that it is the range of these. Although A ₂ O content of the aluminosilicate is preferably as low as, for example, its content is 2 mass% or more, from the viewpoint of production easiness and the like of the adsorbent of the present invention. The content of A ₂ O and Na ₂ O in the aluminosilicate is measured by fluorescent X-ray analysis, specifically by the method of Examples described later.

In order to produce the aluminosilicate having the above-mentioned SiO ₂ , Al ₂ O ₃ , A ₂ O and Na ₂ O content, the adsorbent of the present invention is used in the production method (A) or (B) described later. What is necessary is just to manufacture and to adjust the use ratio of each raw material in that case. As the SiO _2, Al ₂ O _3, the preferred range of the content of A ₂ O and Na ₂ O in the adsorbent of the present invention, SiO _2, Al ₂ O ₃ in the aluminosilicate, A ₂ O and the same range as the numerical range mentioned above can be cited as a preferable range of each content of Na ₂ O.

  The form of the adsorbent of the present invention may be any form such as powder, granular (including columnar, spherical, plate-like, cylindrical, and honeycomb-like), but is a powder having a particle size of 2 μm or more and 2000 μm or less. It is preferable that it can be suitably used for strontium adsorption in seawater. Further, for example, if the adsorbent of the present invention is granulated or molded as necessary, it can be used as an adsorbent for filling an adsorption tower. In this case, it is more preferable that the particle size is 200 μm or more and 10 mm or less. In the case of a granular material having a particle size of 200 μm or more, when the adsorbent of the present invention is packed in the adsorption tower and passed through, it is possible to prevent particles from clogging in the adsorption tower and increase in pressure loss in the adsorption tower. . Further, when the particle size is larger than 10 mm, the adsorption rate of strontium is slowed and the adsorption efficiency is deteriorated. However, the adsorption performance can be improved by setting the particle size to 10 mm or less. From such a viewpoint, the particle size of the adsorbent when the adsorbent of the present invention is used as a granular material is more preferably 300 μm or more and 10 mm or less. Specifically, it can be confirmed that the particle size of the adsorbent of the present invention is in a specific range by using a sieve having an opening corresponding to each particle size according to the JIS Z8801 standard, and 98% by mass or more of the adsorbent of the present invention. When the mesh size passes through a 10 mm sieve and 98% by mass or more does not pass through a sieve having an aperture of 212 μm, the particle size is 200 μm or more and 10 mm or less. Further, when 98% by mass or more of the adsorbent of the present invention passes through a sieve having an aperture of 10 mm and 98% by mass or more does not pass through a sieve having an aperture of 300 μm, the particle size is assumed to be 300 μm or more and 10 mm or less. The adsorbent of the present invention may have a particle size of 2000 μm or less, or 1000 μm or less. When 98% by mass or more of the adsorbent of the present invention passes through a sieve having an opening of 2 mm, the particle size is 2000 μm or less, and when 98% by mass or more of the adsorbent of the present invention passes through a sieve of 1 mm of opening, the particle size is 1000 μm or less.

When the adsorbent of the present invention is a granule having a binder in addition to the aluminosilicate, the amount of the binder in the adsorbent is preferably 30% by mass or less from the viewpoint of enhancing the adsorption performance. It is more preferably 5% by mass or more and 25% by mass or less, and particularly preferably 5% by mass or more and 20% by mass or less. The amount of binder may be, for example, when Na ₂ O and BaO Na ₂ O content and the content of BaO and in the binder before granulation of the powder is known, the Na ₂ O and BaO content of granulate It is measured by measuring and comparing with the content of the powder before granulation. Examples of the binder here include various organic and inorganic materials described later.

  Moreover, it is also preferable to use the adsorbent of this invention with the form fixed to the nonwoven fabric as a form of a powdery body so that it may mention later. In this case, the particle size of the adsorbent is preferably an average particle size of 2 μm or more and 10 μm or less from the viewpoint that the pulverization step can be easily performed in the production process of the adsorbent, and the maximum particle size is 100 μm or less. It is preferable from the viewpoint that the adsorbent particles can be prevented from falling off from the nonwoven fabric when fixed to the nonwoven fabric. From these viewpoints, the particle size of the powdery adsorbent when used fixed to a non-woven fabric is more preferably an average particle size of 2.5 μm to 8 μm and a maximum particle size of 74 μm or less. The average particle diameter here is specifically the particle diameter (D50) at which the integrated volume from the small particle diameter side by the laser diffraction / scattering particle size distribution measurement method is 50%, and the maximum particle diameter is the same measurement. The particle size (D100) at which the cumulative volume from the small particle size side by the method becomes 100%. The average particle size and the maximum particle size are measured by an apparatus using a laser diffraction / scattering type particle size distribution measuring method, and can be measured by, for example, a microtrack by Nikkiso Co., Ltd. or Microtrack Bell.

The adsorbent of the present invention is preferably produced by the following production method (A), (B) or (C).
(A) A method in which Na-A zeolite and a barium-containing aqueous solution are mixed and sodium in the Na-A zeolite is ion-exchanged with barium (hereinafter also referred to as “ion exchange step 1”).
(B) A step of mixing a silicon source, an aluminum source, a barium source, an alkali source, and water, and aging the resulting mixture under heating at 40 ° C. to 100 ° C. Also referred to as “aging process”).
(C) A step of mixing the granular material containing Na-A type zeolite and the barium-containing aqueous solution to ion-exchange sodium in the granular material containing Na-A type zeolite with barium (hereinafter referred to as “ion exchange step 2”). (Also called).

  First, the method (A) will be described. As described above, one of the features of this production method is that Na-A-type zeolite is used as an object to be ion-exchanged with barium ions. This is because the Na-A type zeolite is a zeolite with many Na components that can be ion-exchanged with barium ions. By using this, the barium content of the aluminosilicate contained in the adsorbent obtained is increased. Because it can.

  For Na-A type zeolite ion-exchanged with barium ions, the production history is not particularly limited. Any Na-A zeolite synthesized from any raw material can be used. For example, in addition to general Na-A type zeolite synthesized using sodium silicate, sodium aluminate and caustic soda as raw materials, Na-obtained by reacting coal ash, paper sludge incineration ash, aluminum dross residual ash and the like with alkali. A-type zeolite can also be used.

  Examples of the ion exchange method using barium ions include a method in which an aqueous solution of a water-soluble barium compound and Na-A type zeolite are mixed to obtain a mixed solution. Examples of the water-soluble barium compound include barium chloride, barium nitrate, barium hydroxide, and barium acetate, and these can be used alone or in combination. Since the A-type zeolite is gradually dissolved in the acidic region, a solution which tends to make the pH of the aqueous solution near neutral, for example, barium chloride is preferable from the viewpoint of keeping the crystal structure of the zeolite stable.

  As a condition for ion exchange, it is preferable that the concentration of Na-A zeolite in a slurry obtained by dispersing zeolite in the aqueous solution of the water-soluble barium compound is 3% by mass or more and 30% by mass or less. When the concentration of the Na-A type zeolite in the slurry is increased to 3% by mass or more, the facility for ion exchange can be reduced to a certain scale or less, which is preferable in terms of increasing the facility efficiency. Further, when the concentration of Na-A type zeolite in the slurry is 30% by mass or less, the viscosity of the slurry can be kept to a certain level or less, a stirrer having a large stirring power is unnecessary, and a water-soluble barium compound is added to the slurry. It is preferable because it can be easily dissolved. From this viewpoint, the concentration of the Na-A type zeolite in the slurry is more preferably 5% by mass or more and 25% by mass or less, and particularly preferably 10% by mass or more and 20% by mass or less. Moreover, as a preferable range of the concentration of the slurry obtained by dispersing the Na-A type zeolite in the barium-containing aqueous solution, the same range as the range mentioned above as the preferable range of the concentration of the Na-A type zeolite in the slurry is the same range. Can be mentioned.

  There is no restriction | limiting in particular about the reaction temperature in ion exchange, Heating may be carried out and ion exchange is possible also at normal temperature. The stirring time in ion exchange is preferably about 30 minutes to 5 hours. By setting it as 30 minutes or more, it is easy to prevent the danger that an ion exchange rate will become low. From this viewpoint, the time for continuing stirring in ion exchange (hereinafter also referred to as stirring time) is more preferably 1 hour or longer. When the stirring time exceeds 5 hours, the increase in the ion exchange rate tends to reach saturation, so that the production efficiency can be improved by setting it to 5 hours or less.

The amount of water-soluble barium compound used for ion exchange is the molar ratio of BaO converted from Ba in the slurry obtained by dispersing zeolite in the aqueous solution of water-soluble barium compound described above and Na ₂ O in the zeolite. The amount that BaO / Na ₂ O is 0.04 or more and 1.5 or less is preferable. When this molar ratio is 0.04 or more, the ion exchange rate is easily set to a certain level or more, and the BaO content of the aluminosilicate in the adsorbent obtained by this production method can easily reach 2% by mass. Conversely, when the water-soluble barium compound is used in an amount such that the molar ratio exceeds 1.5, the ion exchange rate reaches saturation, and the water-soluble barium compound tends to remain in the reaction mother liquor and is wasted. In this respect, the molar ratio BaO / Na ₂ O is more preferably 0.2 or more and 1.5 or less, further preferably 0.4 or more and 1.5 or less, and 1.0 or more and 1.5 or less. More preferably, it is the following. After the ion exchange reaction is completed, the slurry after the reaction is filtered by a conventional method, washed with repulp, the obtained washed product is dried, and then the obtained dried product is pulverized to obtain a powdery substance. The adsorbent of the invention can be obtained. The particle size of the powder is preferably 0.4 μm or more and 44 μm or less (the same applies to the method (B)).

  Next, the method (B), that is, a silicon source, an aluminum source, a barium source, an alkali source, and water are mixed, and the obtained mixed liquid is kept under heating at 40 ° C. or higher and 100 ° C. or lower. A method for producing a strontium adsorbent having an aging step will be described.

  Examples of the silicon source include silica and silicon-containing compounds capable of generating silicate ions in water. Specific examples include wet method silica, dry method silica, colloidal silica, sodium silicate, aluminosilicate gel, and the like. These silicon sources can be used alone or in combination of two or more. Of these silicon sources, use of sodium silicate is preferable from the viewpoint of industrial practicality because it is a solution and has good reactivity with an aluminum source and is inexpensive.

  As the aluminum source, for example, a water-soluble aluminum-containing compound or powdered aluminum can be used. Specific examples of the water-soluble aluminum-containing compound include sodium aluminate, aluminum nitrate, and aluminum sulfate. Aluminum hydroxide is also a suitable aluminum source. These aluminum sources can be used alone or in combination of two or more. Of these aluminum sources, it is preferable to use sodium aluminate from the viewpoint that it is a solution and therefore has good reactivity with the silicon source and facilitates production of the aluminosilicate.

  Examples of the barium source include water-soluble barium compounds. Examples of such barium compounds include barium chloride, barium nitrate, barium hydroxide, and barium acetate. These barium sources can be used alone or in combination of two or more. Of these barium sources, it is preferable to use barium chloride or barium hydroxide from the viewpoint of higher solubility than other barium compounds and easy treatment of the waste liquid after ion exchange.

As the alkali source, for example, sodium hydroxide can be used. When sodium silicate is used as the silica source or sodium aluminate is used as the aluminum source, sodium, which is an alkali metal component contained therein, is simultaneously regarded as NaOH and is also an alkali component. For this reason, Na ₂ O described later is calculated as the sum of all alkali components in the mixed solution unless otherwise specified. In addition, in this manufacturing method, it is essential to use sodium as an alkali metal used as an alkali source, and other alkali metal ions such as potassium ion and lithium ion are used in this manufacturing method. Not required.

In this production method, a silicon source, an aluminum source, a barium source, an alkali source, and water are mixed so as to be a mixed liquid having a composition represented by a molar ratio shown below. It is preferable to satisfy the following molar ratio because the adsorbent of the present invention can be easily produced.
In the following the "Al ₂ O ₃ Na ₂ are calculated from A-type zeolite _{Na 2 O · Al 2 O 3} · 2SiO 2 · 4.5H 2 O converted from the charged amount O" is, Al ₂ O ₃ were charged It refers to the amount of Na ₂ O in this zeolite when it is assumed that the same amount of type A zeolite Na ₂ O.Al ₂ O ₃ .2SiO ₂ .4.5H ₂ O is formed. Molar amount of the order "Al ₂ O ₃ Na ₂ is calculated from converted from the charged amount A type zeolite _{Na 2 O · Al 2 O 3} · 2SiO 2 · 4.5H 2 O O " is the Al ₂ O ₃ Equal to the molar amount charged.

SiO ₂ / Al ₂ O ₃ is 1.8 or more and 2.2 or less Na ₂ O / SiO ₂ is 2.0 or more and 3.0 or less A-type zeolite converted from Al ₂ O ₃ charge amount Na ₂ O · Al ₂ O The ratio BaO / Na ₂ O to Na ₂ O calculated from ₃ · 2SiO ₂ · 4.5H ₂ O is 0.04 to 1.5, preferably 0.4 to 1.5

In the composition of the mixed solution, the particularly preferable molar ratio includes the following ranges.
SiO ₂ / Al ₂ O ₃ is 1.9 or more and 2.1 or less Na ₂ O / SiO ₂ is 2.1 or more and 2.7 or less A-type zeolite converted from Al ₂ O ₃ charge amount Na ₂ O · Al ₂ O ₃ · 2SiO ₂ · 4.5H ₂ ratio BaO / Na ₂ O of BaO molar equivalents relative molar equivalent of Na ₂ O, which is calculated from the O 0.5 to 1.2

  The order of addition of each raw material to obtain a mixed liquid is as follows: a silicon-containing liquid obtained by mixing water and a silicon source, an aluminum-containing liquid obtained by mixing water and an aluminum source, and a water and barium source A method of preparing each of the barium-containing liquids obtained by mixing and mixing these three liquids is preferable from the viewpoint of easily obtaining the adsorbent of the present invention. The alkali source may be added in advance to any one or more of the silicon-containing liquid, the aluminum-containing liquid, and the barium-containing liquid, or is obtained by mixing all of the silicon-containing liquid, the aluminum-containing liquid, and the barium-containing liquid. You may mix an alkali source with a liquid mixture. Preferably, an alkali source is contained in the silicon-containing liquid and / or the aluminum-containing liquid before mixing.

The method of mixing the silicon-containing liquid, the aluminum-containing liquid and the barium-containing liquid is, for example, preferably the following methods (1) to (3), more preferably the methods (1) and (3), and the method (1). Is particularly preferred.
(1) Method of mixing silicon-containing liquid and barium-containing liquid, and mixing aluminum-containing liquid with the obtained mixed liquid (2) Mixing aluminum-containing liquid and barium-containing liquid, and silicon-containing liquid into the obtained mixed liquid (3) A method of mixing a silicon-containing liquid and an aluminum-containing liquid, and mixing a barium-containing liquid with the obtained mixed liquid

The liquid mixture obtained by mixing the silicon source, the aluminum source, the barium source, the alkali source, and water as described above is aged while being kept under heating at 40 ° C. or higher and 100 ° C. or lower. From the viewpoint of enhancing the performance of the adsorbent obtained, the heating temperature is preferably 50 ° C. or higher and 100 ° C. or lower, and more preferably 60 ° C. or higher and 95 ° C. or lower. Further, on the assumption that the heating temperature is in the above range, the heating time is preferably 1 hour or more and 10 hours or less, and more preferably 2 hours or more and 5 hours or less.
This aging step can be performed under normal pressure.

  The slurry after the aging reaction is filtered by a conventional method, then washed with repulp, the obtained washed product is dried, and then the obtained dried product is pulverized to obtain a powdery adsorbent.

Next, the method of (C), that is, an ion exchange step of mixing the granular material containing Na-A type zeolite and the barium-containing aqueous solution to ion-exchange sodium in the granular material containing Na-A type zeolite with barium. The manufacturing method of the strontium adsorbent which has 2 is demonstrated.
In addition, in this invention, compared with the adsorbent which processed the powdery body obtained by the manufacturing method of (A) or (B) mentioned above into the granular material by employ | adopting the manufacturing method of (C), granular material itself In the present invention, the method (C) is preferably employed particularly in the case of obtaining a particulate adsorbent, since the durability of the strontium is further improved and the strontium adsorption ability is further improved.

The granule containing the Na-A type zeolite is obtained by kneading the Na-A type zeolite and a binder, then forming into a desired shape, drying, and firing if necessary.
Examples of the shape of the granular material containing Na-A zeolite include a spherical shape, a plate shape, a columnar shape, a cylindrical shape, and a honeycomb shape. In this manufacturing method, the shape of the granular material containing Na-A type zeolite can be used as it is as the shape of the adsorbent of the final product. For this reason, it is preferable to select the shape of the granular material containing the Na-A type zeolite used in consideration of the shape of the final adsorbent.

The granular material containing Na-A type zeolite is capable of securing Na capable of Ba ion exchange and containing Na-A type zeolite in an amount of 50% by mass or more, preferably 70% by mass or more and 95% by mass or less. ) Is also preferable from the viewpoint of being in an appropriate amount range.
The granular material containing Na-A type zeolite is more preferably a granular material having a particle size of 200 μm or more and 10 mm or less, and more preferably 300 μm or more and 10 mm or less.
The granule containing Na-A type zeolite can be produced by a known method, and the granule itself containing Na-A type zeolite is commercially available, and these commercially available products can also be suitably used. .

An example of a method for producing a granular material containing Na-A type zeolite is as follows. After kneading Na-A type zeolite and a binder, it is molded into a desired shape, dried, and calcined as necessary. Can be manufactured.
Regarding the Na-A type zeolite, the production history is not particularly limited. Any Na-A zeolite synthesized from any raw material can be used. For example, in addition to general Na-A zeolite synthesized using sodium silicate, sodium aluminate and caustic soda as raw materials, Na-obtained by reacting coal ash, paper sludge incineration ash, aluminum dross residual ash and the like with alkali. A-type zeolite can also be used.
There is no restriction | limiting in particular as said binder. Either or both of an inorganic binder (hereinafter referred to as “inorganic binder”) and an organic binder (hereinafter referred to as “organic binder”) can be used.
Examples of the inorganic binder include sodium silicate, sodium aluminate, silica sol, alumina sol, titania sol, zirconia sol, kaolinite, halloysite, volclay, bentonite, acid clay, attapulgite, hectorite, kibushi clay, sepiolite, and other kaolin systems, Examples include clay minerals such as smectite group and palygorskite group plastic clay, and these can be used alone or in combination of two or more.
Examples of the organic binder include cellulosic materials such as carboxymethyl cellulose and hydroxyethyl cellulose, and polymer materials such as polyethylene glycol and polyethylene oxide, which can be used alone or in combination of two or more.
The amount of the binder to be added is preferably small, but from the viewpoint of the strength of the molded body, the non-Na-A type zeolite component in the molded body is 25% by mass or less, often 10% by mass to 25% by mass. It mix | blends so that it may become the following ranges. If desired, in addition to the binder, a small amount of cellulose powder or water-soluble polymer may be blended in order to adjust the micropores of the molded body.
Such a mixture is kneaded with an appropriate amount of water and then molded or granulated with a desired molding machine. In general, extrusion molding or rolling granulation is preferred.
In order to obtain strength, the obtained granule is dried at, for example, about 100 to 120 ° C., and then calcined at 500 to 700 ° C., if necessary, to obtain a granule containing Na-A type zeolite. I can do it.

Since the ion exchange method using barium ions and the reaction temperature in the ion exchange can be performed in accordance with the method of the ion exchange step 1 of (A) described above, other conditions will be described below.
As a condition for ion exchange, the concentration of the granular material containing Na-A zeolite in the slurry obtained by dispersing the granular material containing Na-A zeolite in an aqueous solution of a water-soluble barium compound is preferably 5% by mass. More than 50 mass%, more preferably 7 mass% or more and 30 mass% or less is preferable from the viewpoint that the capacity of the exchange tank used for ion exchange is appropriately maintained and loose stirring is possible during the ion exchange reaction. is there. In addition, as a preferable range of the concentration of the slurry obtained by dispersing the granular material containing Na-A type zeolite in the barium-containing aqueous solution, the preferable range of the concentration of the granular material containing Na-A type zeolite in the slurry is as described above. The range similar to the range mentioned in (4) is mentioned. From the same viewpoint as described above, a preferable range of the concentration of the Na-A type zeolite in the slurry obtained by dispersing the granular material containing the Na-A type zeolite in the aqueous solution of the water-soluble barium compound is 3% by mass or more. It is preferably 30% by mass or less, more preferably 5% by mass or more and 25% by mass or less, and particularly preferably 10% by mass or more and 20% by mass or less.

As the amount of the water-soluble barium compound used for ion exchange, BaO converted from Ba in the slurry obtained by dispersing the granular material containing Na-A type zeolite in the aqueous solution of the water-soluble barium compound, Na- mole ratio BaO / Na ₂ O with Na ₂ O of the granulate containing the a-type zeolite, preferably an amount that 0.04 to 1.5. When this molar ratio is 0.04 or more, the ion exchange rate is easily set to a certain level or more, and the BaO content of the aluminosilicate in the adsorbent obtained by this production method can easily reach 2% by mass. Conversely, when the water-soluble barium compound is used in an amount such that the molar ratio exceeds 1.5, the ion exchange rate reaches saturation, and the water-soluble barium compound tends to remain in the reaction mother liquor and is wasted. After the ion exchange reaction is completed, the slurry after the reaction is filtered by a conventional method, then repulp washed if necessary, the obtained washed product is dried, and then the obtained dried product is crushed as necessary. An adsorbent comprising a granular material can be obtained. In this respect, the molar ratio BaO / Na ₂ O is more preferably 0.2 or more and 1.5 or less, further preferably 0.4 or more and 1.5 or less, and 1.0 or more and 1.5 or less. More preferably, it is the following.

The adsorbent of the present invention obtained by the method (A) or (B) as described above is processed into a powder as it is when used for various adsorbing sheets and mats such as non-woven fabrics. It is used by adding at the time. As a specific method for fixing the adsorbent to the nonwoven fabric, there is a method in which a powdery adsorbent is dispersed in water together with an emulsified resin binder, and the nonwoven fabric is impregnated and dried, followed by drying. Examples of the resin binder include latex binder, polyacrylate, polymethacrylate, acrylate copolymer, methacrylate copolymer, styrene butadiene copolymer, styrene acrylic copolymer, ethylene vinyl acetate copolymer, and nitrile rubber. , Acrylonitrile butadiene copolymer, polyvinyl alcohol and the like. As the nonwoven fabric, for example, those composed of polyester and / or polyolefin fibers are used. Before fixing to the nonwoven fabric, it is preferable to adjust the particle size of the adsorbent to a range of the above average particle diameter of 2 μm to 10 μm as necessary.
Thus, the nonwoven fabric which apply | coated the adsorbent can be used suitably for water treatment, for example by setting it as the form wound by making the surface which apply | coated the adsorbent inside.
In addition, as a method of immobilizing the powdery adsorbent of the present invention on the nonwoven fabric, the Na-A-type zeolite may be immobilized on the nonwoven fabric as described above, and then ion exchange treatment with barium ions may be performed. Good.

  When processing the adsorbent of this invention which is a powdery body obtained by the manufacturing method of said (A) or (B) into a granular material, a binder is normally used. There is no restriction | limiting in particular as this binder. Either or both of an inorganic binder (hereinafter referred to as “inorganic binder”) and an organic binder (hereinafter referred to as “organic binder”) can be used.

  Examples of the inorganic binder include clay minerals such as sodium silicate, sodium aluminate, silica sol, alumina sol, titania sol, zirconia sol, bentonite and montmorillonite, and these can be used alone or in combination of two or more.

  Examples of the organic binder include cellulosic materials such as carboxymethyl cellulose and hydroxyethyl cellulose, and polymer materials such as polyethylene glycol and polyethylene oxide, which can be used alone or in combination of two or more.

  When the adsorbent of the present invention, which is a powdered body, is made into a granular body using these various binders, the various binders are kneaded with a kneader or the like, then molded with an extrusion granulator or the like, and dried. After firing as necessary, the particles may be sized to a predetermined particle size by a method such as crushing.

  The granular adsorbent obtained by granulating the powdery adsorbent obtained by the production methods (A) and (B) above is packed in an adsorption vessel or adsorption tower and contains a radioactive strontium water treatment system. It can be suitably used as an adsorbent. Moreover, the powder obtained by the method (C) can be suitably used as an adsorbent for a water treatment system containing a radioactive strontium as it is filled in an adsorption vessel or an adsorption tower. However, the present invention is not limited to this form, and the adsorbent of the present invention can be suitably used as an adsorbent for a water treatment system containing radioactive strontium as various forms such as fixing to a nonwoven fabric.

  Hereinafter, the present invention will be described with reference to examples. Unless otherwise specified, “%” represents “mass%”. The evaluation apparatus and measurement conditions used in the examples are as follows.

<Evaluation equipment and measurement conditions>
X-ray diffraction: Measurement conditions were as described above.
ICP-AES: Varian 720-ES was used. The Ca and Sr concentrations were measured with a measurement wavelength of Ca of 373.690 nm and a measurement wavelength of Sr of 216.596 nm. The standard sample used was an aqueous solution of artificial seawater with Ca 408.9 ppm and Sr 7.19 ppm.
-X-ray fluorescence analysis: ZSX100e manufactured by Rigaku Corporation was used. Measurement conditions were tube element: Rh (4 kW), atmosphere: vacuum, analysis window material: Be (thickness 30 μm), measurement mode: SQX analysis (EZ scan), measurement diameter: 30 mmφ, and all element measurements were performed. The measurement results were displayed in terms of oxide.

Examples 1 to 5 below are examples in which an aluminosilicate is produced by the production method of (A) and used as an adsorbent.
<Example 1>
A 20% slurry was prepared by dispersing 50 g of Na-A type zeolite (Na-100P manufactured by Nippon Chemical Industry Co., Ltd.) in 200 g of ion-exchanged water. A 20% aqueous solution of barium chloride was prepared, and an aqueous solution of barium chloride corresponding to 0.4 equivalent of Na ₂ O (17.0%) of Na-A zeolite was added. The proportion of Na-A type zeolite in the slurry after addition of barium was 16.3%. The resulting slurry was heated to 50 ° C., and stirring was continued at 50 ° C. for 2 hours to perform ion exchange. After the ion exchange was completed, filtration, repulp washing, drying, and pulverization were performed by a conventional method to obtain an aluminosilicate sample of Example 1. The particle size of this sample was in the range of 0.4 μm to 22 μm.

<Example 2>
The aluminosilicate sample of Example 2 was prepared in the same manner as in Example 1 except that an aqueous barium chloride solution corresponding to 1.2 equivalents of Na ₂ O (17.0%) of the Na-A type zeolite was added. Obtained. The particle size of this sample was in the range of 0.4 μm to 22 μm. Moreover, the ratio of the Na-A type zeolite to the slurry obtained by mixing the Na-A type zeolite and the barium chloride aqueous solution was 11.9%.

<Example 3>
The aluminosilicate sample of Example 3 was prepared in the same manner as in Example 1 except that an aqueous barium chloride solution corresponding to 1.5 equivalents of Na ₂ O (17.0%) of Na-A zeolite was added. Obtained. The particle size of this sample was in the range of 0.4 μm to 22 μm. Moreover, the ratio of the Na-A type zeolite to the slurry obtained by mixing the Na-A type zeolite and the barium chloride aqueous solution was 10.8%.

<Example 4>
16.7% slurry was prepared by dispersing 50 g of Na-A type zeolite (Nippon Chemical Industry Co., Ltd. Na-100P) in 300 g of ion-exchanged water. A 20% aqueous solution of barium chloride was prepared, and an aqueous solution of barium chloride corresponding to 0.05 equivalent of Na ₂ O (17.0%) of Na-A type zeolite was added. The proportion of Na-A type zeolite in the slurry after addition of barium was 16.3%. The resulting slurry was heated to 50 ° C., and stirring was continued at 50 ° C. for 2 hours to perform ion exchange. After the ion exchange, filtration, repulp washing, drying and pulverization were carried out by a conventional method to obtain an aluminosilicate sample. The particle size of this sample was in the range of 0.4 μm to 22 μm.

<Example 5>
16.7% slurry was prepared by dispersing 50 g of Na-A type zeolite (Nippon Chemical Industry Co., Ltd. Na-100P) in 300 g of ion-exchanged water. A 20% aqueous solution of barium chloride was prepared, and an aqueous solution of barium chloride corresponding to 0.1 equivalent of Na ₂ O (17.0%) of Na-A type zeolite was added. The proportion of Na-A type zeolite in the slurry after addition of barium was 15.9%. The resulting slurry was heated to 50 ° C., and stirring was continued at 50 ° C. for 2 hours to perform ion exchange. After the ion exchange, filtration, repulp washing, drying and pulverization were carried out by a conventional method to obtain an aluminosilicate sample. The particle size of this sample was in the range of 0.4 μm to 22 μm.

<Comparative Example 1>
Na-A type zeolite (Na-100P manufactured by Nippon Chemical Industry Co., Ltd.) itself was used as the aluminosilicate sample of Comparative Example 1.

<Comparative Example 2>
Aluminosilicate of Comparative Example 2 in the same manner as in Example 1 except that Y-type zeolite (manufactured by Nippon Chemical Industry Co., Ltd.) was used instead of Na-A type zeolite (Nippon Chemical Industry Co., Ltd. Na-100P). A salt sample was obtained. This Y-type zeolite is produced as follows.
Aqueous solution of sodium aluminate _{(Al 2 O 3 20.3%,} Na 2 O18.9%, H 2 O60.8%) 167.1kg 25% caustic soda 97.1Kg, and mixed with ion-exchanged water 232.1kg As a result, 496.3 kg of an aluminum preparation solution was prepared. No. 3 sodium silicate (SiO ₂ 29.0%, Na ₂ O 9.5%, H ₂ O 61.5%) 698.3 kg, white carbon 71.2 kg and ion-exchanged water 300 kg were added and mixed to prepare a silica preparation solution 1069.5 kg was prepared. A silica preparation solution was added to the aluminum preparation solution to prepare a sodium aluminosilicate gel. The composition of this gel is as follows.
_{SiO 2 / Al 2 O 3 =} 13.35, Na 2 O / SiO 2 = 0.42, H 2 O / Na 2 O = 33.70
This sodium aluminosilicate gel was stirred at room temperature for 48 hours and then crystallized at 93 ° C. for 48 hours. The obtained crystallized product was filtered, washed, dried and pulverized by a conventional method to obtain a Y-type zeolite.

[Measurement and evaluation]
The following measurements and evaluations were performed for each sample of each example and comparative example.

<Aluminosilicate composition analysis>
X-ray fluorescence analysis was performed using the above measuring apparatus and conditions, and the contents of Na ₂ O, SiO ₂ , Al ₂ O ₃ and BaO in the aluminosilicate samples of the examples and comparative examples were measured. Further, the Ba ion exchange rate was calculated from the obtained BaO content.
The Ba ion exchange rate was calculated by dividing the obtained BaO content by 40.8% using 40.8%, which is the theoretical maximum value of the BaO content in the aluminosilicate, as a reference value. . These results are shown in Table 1 below.

<X-ray diffraction measurement>
X-ray diffraction measurement was performed under the measurement conditions described above. The angles (°) and relative intensities (I / I ₀ ) of the diffraction peaks detected by X-ray diffraction measurement of the aluminosilicate samples of Examples 1 to 5 are shown in Tables 2A to 2E. Further, FIG. 1 shows a chart obtained by performing X-ray diffraction measurement on the Na-A type zeolite which is Comparative Example 1 and the aluminosilicate of Example 1 (before and after the adsorption test). As is clear from FIG. 1, as is clear from a comparison between the Na-A type zeolite (upper part) of Comparative Example 1 and the aluminosilicate of Example 1 (lower part, before the adsorption test), In aluminosilicate (lower stage), at least 29.8 ° to 30.2 °, 23.8 ° to 24.2 °, 7.0 ° to 7. Diffraction peaks are observed in respective ranges of 4 ° or less, 10.0 ° or more and 10.6 ° or less, and 12.4 ° or more and 12.8 ° or less (this point is also confirmed from Table 2A). Compared to the diffraction peak of Example 1 (before the adsorption test) in the lower part of FIG. 1, Example 1 (after the adsorption test) in the middle part has 2θ = 20.5 °, 23 °, 25 °, 29 °, 32 °, BaSO ₄ diffraction peaks are observed at 33 ° and 43 °. In addition, it is clear from Tables 2B to 2E that diffraction peaks are observed in the same range as in Example 1 in the samples of Examples 2 to 5.

  Also, from FIG. 1, the aluminosilicate of Example 1 obtained by ion-exchange of Na-A type zeolite with Ba ions has each crystal diffraction peak intensity reduced to 15-20% of Na-A zeolite. , Indicating that the crystallinity was lowered and changed to low crystalline barium aluminosilicate. In the aluminosilicate of Example 1, a new diffraction peak of barium sulfate appeared in the diffraction peak after adsorption of strontium, indicating that barium sulfate was produced by the reaction of sulfate ions in seawater with barium ions of barium silicate. Show.

<Adsorption test>
After putting 0.1 g of the aluminosilicate sample obtained in each Example and each Comparative Example into 100 ml of artificial seawater (artificial seawater marine art SF-1 for test research, manufactured by Tomita Pharmaceutical Co., Ltd.) and stirring for 1 hour with a stirrer, ICP-AES analysis was performed on Mg, Ca, and Sr of the liquid according to the measurement apparatus and conditions described above. The obtained adsorption test results are shown in Table 3 below. As for Mg ions, all samples were not adsorbed at all, so the data relating to Mg ions was omitted in Table 3 (the same applies to Table 5 below).
The content of the main components in an artificial sea water, NaCl; 22.1g / L, MgCl 2 · 6H 2 O; 9.9g / L (Mg: 1184ppm), CaCl 2 · 2H 2 O; 1.5g / L (Ca: 409 ppm), Na ₂ SO ₄ ; 3.9 g / L (SO ₄ : 2637 ppm), KCl; 0.61 g / L, SrCl ₂ ; 13 mg / L (Sr: 7.2 ppm).

  From the results of Table 3 above, the aluminosilicate obtained in each example has a significantly higher strontium adsorption rate than the calcium adsorption rate in artificial seawater having a much higher calcium concentration than strontium. It can be seen that the ability to adsorb strontium is very high. Compared to these, it can be seen that the strontium adsorption performance is significantly inferior in the aluminosilicate of each comparative example. Therefore, it is clear that the aluminosilicate of each example is suitable as a strontium adsorbent.

  Examples 6 to 8 below are examples in which an aluminosilicate was produced by the production method (B) and used as an adsorbent.

<Example 6>
A sodium aluminate aqueous solution (hereinafter also referred to as A liquid), a sodium silicate aqueous solution (hereinafter also referred to as S liquid) and a barium hydroxide aqueous solution (hereinafter also referred to as B liquid) were prepared as follows.
Preparation of liquid A: Sodium aluminate, caustic soda, and ion-exchanged water were mixed to prepare an aqueous solution of Na ₂ O 14.05% and Al ₂ O ₃ 8.27%.
Preparation of solution S: No. 3 sodium silicate, caustic soda, and ion-exchanged water were mixed to prepare an aqueous solution of 10.76% Na ₂ O and 10.00% SiO ₂ .
Preparation of solution B: Barium hydroxide was dissolved in warm water (about 40 ° C.) to prepare a 6.0% aqueous solution of BaO.
First, 100 g of S liquid and 200 g of B liquid were mixed. Next, the obtained mixed liquid and 100 g of A liquid were mixed. The obtained mixed slurry was subjected to reaction aging at 90 ° C. for 2 hours. The slurry after completion of aging was filtered, repulp washed, dried and pulverized by a conventional method to obtain an aluminosilicate sample of Example 6. The particle size of this sample was in the range of 0.4 μm to 37 μm.

<Example 7>
In Example 6, when obtaining a mixed slurry from liquid A, liquid B and liquid S, first, 100 g of liquid A and liquid 200 g are mixed, and then the liquid mixture obtained is mixed with liquid 100 g. Thus, an aluminosilicate sample of Example 7 was obtained in the same manner as Example 6 except that a mixed slurry was obtained. The particle size of this sample was in the range of 0.4 μm to 37 μm.

<Example 8>
In Example 6, when obtaining a mixed slurry from liquid A, liquid B and liquid S, first, 100 g of liquid A and liquid 100 g were mixed, and then the obtained liquid mixture and liquid B were mixed and mixed 200 g. An aluminosilicate sample of Example 8 was obtained in the same manner as in Example 6 except that the slurry was obtained. The particle size of this sample was in the range of 0.4 μm to 37 μm.

[Measurement and evaluation]
“Molar ratio SiO ₂ / Al ₂ O ₃ ”, “Molar ratio Na ₂ O / SiO ₂ ” and “Al” in the mixed slurry obtained by mixing the liquid A, liquid B and liquid S in Examples 6 to 8 ₂ O ₃ a-type zeolite was converted from the charged amounts _{Na 2 O · Al 2 O 3} · 2SiO 2 · 4.5H 2 O is calculated from Na ₂ O BaO molar amounts of the ratio BaO / Na ₂ O with respect to the molar amount of Is shown in Table 3 below. Regarding aluminosilicate samples obtained in Examples 6-8, perform fluorescent X-ray analysis by measuring equipment and conditions described above, Na ₂ O in the sample of Example _{6~8, SiO 2, Al 2 O} 3 and The content of BaO was measured. The results are shown in Table 4 below.

  Furthermore, the X-ray diffraction measurement was performed on the aluminosilicate samples obtained in Examples 6 to 8 using the above measuring apparatus and conditions. The angles of diffraction peaks detected by X-ray diffraction measurement of the aluminosilicate samples of Examples 6 to 8 are shown in Tables 5A to 5C. Moreover, the diffraction chart obtained by the X-ray-diffraction measurement of the aluminosilicate sample of Examples 6-8 is shown in FIG. As is clear from Tables 5A to 5C and FIG. 2, the aluminosilicates obtained in Examples 6 to 8 are all 29.8 ° or more and 30.2 ° or less, and 23.8 ° or more and 24.2 °. In the following, diffraction peaks are observed in each range of 7.0 ° to 7.4 °, 10.0 ° to 10.6 °, and 12.4 ° to 12.8 °.

  Moreover, the same <adsorption test> was performed about the aluminosilicate sample of Examples 6-8. The results obtained are shown in Table 6 below.

  From the results shown in Table 6, in Examples 6-8, the aluminosilicate produced by the aging process instead of the ion exchange process is high, similar to the aluminosilicate of Examples 1-5 produced by the ion exchange process. It can be seen that it has selective adsorption performance of strontium. Therefore, it is clear that the aluminosilicates obtained in Examples 6 to 8 are also suitable as a strontium adsorbent like the aluminosilicates of Examples 1 to 5.

<Example 9>
83 parts by weight of Na-A type zeolite (Nippon Chemical Industry Co., Ltd. Na-100P) and 17 parts by weight of bentonite were mixed, and water was sprayed while the mixture was fed to a dish type granulator (diameter 600 mm). Rolling granulation was performed. After granulation, the granulated product was dried at 110 ° C. for 2 hours and then calcined at 650 ° C. for 2 hours. The calcined product is classified with a sieve of 850 μm and 1.4 mm, and a granular material containing spherical Na-A type zeolite (hereinafter also simply referred to as Na-A type zeolite granular material) (size: 1 mmφ, Na-A type zeolite) A content of 83%) was prepared.
17.0 g of barium chloride dihydrate was dissolved in ion exchange water to prepare a total amount of 340 g. Here, 30 g of the Na-A type zeolite granular material prepared above was put. The proportion of Na-A type zeolite in the slurry after the addition of Na-A type zeolite granules was 8.1%. The molar ratio BaO / Na ₂ O between BaO converted from Ba in the slurry and Na ₂ O in the granular material containing Na-A type zeolite was 1.01. While the resulting slurry was gently stirred, the liquid temperature was adjusted to 50 ° C. and stirring was continued for 6 hours. After completion of stirring, the entire amount was emptied through a 300 μm sieve, drained, thoroughly washed with ion-exchanged water, and then dried at 110 ° C. for one day to obtain an adsorbent sample.
Component analysis by fluorescent X-rays was performed for each of the Na-A type zeolite granules before the ion exchange treatment and the obtained adsorbent sample using the above-described measurement apparatus and conditions. The results are shown in Table 7. Moreover, the X-ray diffraction measurement was performed about the obtained adsorbent sample with the said measuring apparatus and conditions. Table 8 shows the angle (°) and relative intensity (I / I ₀ ) of the diffraction peak detected by X-ray diffraction measurement of the adsorbent sample of Example 9. As shown in the table, the adsorbent sample of Example 9 is 29.8 ° or more and 30.2 ° or less, 23.8 ° or more and 24.2 ° or less, and 7.0 ° or more and 7.4 ° or less. Diffraction peaks are observed in each range of 0 ° to 10.6 ° and 12.4 ° to 12.8 °.

<Example 10>
85 parts by mass of Na-A type zeolite (Nippon Chemical Industry Co., Ltd. Na-100P) and 15 parts by mass of bentonite were mixed, and water was sprayed while the mixture was fed to a dish type granulator (diameter 600 mm). Rolling granulation was performed. After granulation, the granulated product was dried at 110 ° C. for 2 hours and then calcined at 650 ° C. for 2 hours. The calcined product was classified with 1.7 mm and 2.36 mm sieves to prepare spherical Na-A type zeolite granules (size: 2 mmφ, Na-A type zeolite content 85%).
Next, a reaction was performed in the same manner as in Example 9 to obtain an adsorbent sample. The proportion of Na-A type zeolite in the slurry after the addition of Na-A type zeolite granules was 8.1%. The molar ratio BaO / Na ₂ O between BaO converted from Ba in the slurry and Na ₂ O in the granular material containing Na-A type zeolite was 0.99.
When the adsorbent sample obtained after the ion exchange treatment was measured with the above measuring apparatus and conditions, the BaO content in the adsorbent was 21.1%.
Moreover, the X-ray diffraction measurement was performed about the obtained adsorbent sample with the said measuring apparatus and conditions. Table 9 shows the angle (°) and relative intensity (I / I ₀ ) of the diffraction peak detected by X-ray diffraction measurement of the adsorbent sample of Example 10. As shown in the table, the adsorbent sample of Example 10 has 29.8 ° to 30.2 °, 23.8 ° to 24.2 °, and 7.0 ° to 7.4 °. Diffraction peaks are observed in each range of 0 ° to 10.6 ° and 12.4 ° to 12.8 °.

<Example 11>
Instead of 83 parts by mass of spherical Na-A type zeolite granules (size: 1 mmφ, Na-A type zeolite content 83%), commercially available columnar Na-A type zeolite granules (size: 1/16 inch φ, long The reaction was carried out in the same manner as in Example 9 except that 83 parts by mass of 2-7 mm, Na-A type zeolite content estimated 90%, Wako Pure Chemical Industries, Ltd. Molecular Sieve 4A 1/16) was used, and the adsorbent A sample was obtained. The proportion of Na-A type zeolite in the slurry after the addition of Na-A type zeolite granules was 8.1%. The molar ratio BaO / Na ₂ O between BaO converted from Ba in the slurry and Na ₂ O in the granule containing Na-A type zeolite was 0.93.
Component analysis by fluorescent X-rays was performed for each of the Na-A type zeolite granules before the ion exchange treatment and the obtained adsorbent sample using the above-described measurement apparatus and conditions. The results are shown in Table 10. Moreover, the X-ray diffraction measurement was performed about the obtained adsorbent sample with the said measuring apparatus and conditions. Table 11 shows the diffraction peak angle (°) and relative intensity (I / I ₀ ) detected by X-ray diffraction measurement of the adsorbent sample of Example 11. As shown in the table, the adsorbent sample of Example 11 has 29.8 ° to 30.2 °, 23.8 ° to 24.2 °, and 7.0 ° to 7.4 °. Diffraction peaks are observed in each range of 0 ° to 10.6 ° and 12.4 ° to 12.8 °.

Moreover, about the adsorbent sample of Examples 9-11, the test similar to the strontium adsorption test in said <adsorption test> was done. The results obtained are shown in Table 12 below.

  From the results shown in Table 12, the adsorbent samples produced in Examples 9 to 11 have high strontium selective adsorption performance, similar to the adsorbent samples obtained in Examples 1 to 8, and the strontium adsorbents. It is clear that it is suitable as.

Claims (8)

  A strontium adsorbent comprising an aluminosilicate containing barium, which is at least 29.8 ° to 30.2 °, 23.8 ° to 24.2 °, and 7.0 ° by powder X-ray diffraction. A strontium adsorbent exhibiting a Na-A-type zeolite-like diffraction pattern in which a diffraction peak is observed at 7.4 ° or less.   The strontium adsorbent according to claim 1, wherein the content of BaO in the aluminosilicate is 2% by mass or more and 38% by mass or less.   The strontium adsorbent according to claim 1 or 2, comprising a powder having a particle size range of 2 µm or more and 2000 µm or less.   The strontium adsorbent according to claim 1 or 2, comprising a granular material containing the aluminosilicate. A method for producing a strontium adsorbent according to claim 1,
A step of mixing Na-A type zeolite and a barium-containing aqueous solution to ion-exchange sodium in Na-A type zeolite with barium;
Wherein in the step, it becomes Na-A type zeolite and 30% by weight or less proportion than 3 wt% of Na-A type zeolite occupied in the mixed liquid after mixing with the barium-containing solution, and, BaO / Na ₂ A method for producing a strontium adsorbent, wherein Na-A type zeolite and the barium-containing aqueous solution are mixed at a mixing ratio such that the molar ratio of O is 0.04 or more and 1.5 or less. A method for producing a strontium adsorbent according to claim 1,
A silicon source, an aluminum source, a barium source, an alkali source, and water are mixed so that a mixed liquid having a composition represented by the molar ratio shown below is obtained. The manufacturing method of a strontium adsorbent which has the process to hold | maintain and age | cure | ripen under a heating below ℃.
SiO ₂ / Al ₂ O ₃ is 1.8 or more and 2.2 or less Na ₂ O / SiO ₂ is 2.0 or more and 3.0 or less A-type zeolite converted from Al ₂ O ₃ charge amount Na ₂ O · Al ₂ O ₃ · 2SiO ₂ · 4.5H ₂ BaO against Na ₂ O, which is calculated from the O ratio BaO / Na ₂ O is 0.04 to 1.5 A method for producing a strontium adsorbent according to claim 4,
A method for producing a strontium adsorbent comprising a step of mixing a granular material containing Na-A type zeolite and a barium-containing aqueous solution and ion-exchanging sodium in the granular material containing Na-A type zeolite with barium. In the step, the proportion of the Na-A type zeolite in the mixed solution after mixing the granular material containing the Na-A type zeolite and the barium-containing aqueous solution is 3% by mass or more and 30% by mass or less, and The granular material containing Na-A zeolite and the barium-containing aqueous solution are mixed at a mixing ratio such that the molar ratio of BaO / Na ₂ O is 0.04 or more and 1.5 or less. A method for producing a strontium adsorbent.