JP6263067B2 - Porous titanate ion exchanger - Google Patents

Description

  The present invention relates to a porous ion exchanger that exchanges ions.

  Conventionally, it has been proposed to use an alkali metal titanate compound as an ion exchanger in order to remove or incorporate specific ions (for example, see Non-Patent Document 1). However, when an alkali metal titanate compound is added to water, the particles easily disintegrate and become fine particles. In addition to a decrease in adsorption performance, there is a problem that the ions flow out to the outside together with the adsorbed specific ions. This problem is presumed to be caused by the fact that the alkali metal titanate compound has a high hygroscopic property, so that when it is put into water, the aggregates swell and the particles collapse. That is, the conventionally used alkali metal titanate compound has a problem in durability.

JP2013-76628A JP2013-246145A

Masumi Kubota, 5 others, “Development of group separation method: Development of treatment method of waste liquid containing 90Sr and 137Cs by inorganic ion exchanger column method”, JAERI-M report, Japan Atomic Energy Research Institute, October 1982

  Therefore, as a method for improving the strength of the alkali metal titanate compound, a method of coating a polymer material on the surface of the alkali metal titanate compound (see, for example, Patent Document 1) or a method of coating an inorganic material on the surface of the alkali metal titanate compound. (See, for example, Patent Document 2).

  However, when the strength of the alkali metal titanate compound is improved by the above method, a relatively large amount of a binder containing a polymer material or an inorganic material is required, and the content ratio of the alkali metal titanate compound per unit weight is decreased. As a result, the ion exchange performance of the alkali metal titanate compound is significantly reduced.

  In view of the above problems, an object of the present invention is to provide a porous titanate ion exchanger excellent in both strength and ion exchange performance.

In order to achieve the above object, a porous titanate ion exchanger according to the present invention comprises a layered structure alkali metal titanate compound having a chain structure of at least one TiO ₅ triangular bipyramidal, and at least one TiO ₆ eight. It is set as the structure (1st structure) which consists of a layered structure alkali metal titanate compound which has a chain structure of a plane.

In addition, the porous titanate ion exchanger having the above first structure has a layered structure titanium having a chain structure of the TiO ₅ triangular bipyramidal to the layered structure alkali metal titanate having the chain structure of the TiO ₆ octahedron. The weight ratio of the acid-alkali metal compound is preferably 0.2 to 2.0 (second configuration).

In addition, the porous titanate ion exchanger having the above first or second configuration includes a layered structure alkali metal titanate compound having a chain structure of the TiO ₅ triangular bipyramid, an aggregate, or a granulation A structure (third structure) in which at least a part of the surface of the body is covered with a layered structure alkali metal titanate compound having a chain structure of the TiO ₆ octahedron is preferable.

In addition, the porous titanate ion exchanger having any one of the first to third configurations has a layered structure alkali metal titanate compound having a chain structure of the TiO ₅ triangular bipyramidal (K _1-x H _x ). ₂ Ti ₂ O ₅ · mH ₂ O [0 ≦ x <1, m ≧ 0] (4th configuration).

Further, in the porous titanate ion exchanger having any one of the first to fourth structures, the layered structure alkali metal titanate compound having a chain structure of the TiO ₆ octahedron is (M _1-x H _x ) _2. Ti _n O _{2n + 1} · mH ₂ O [0 ≦ x <1, m ≧ 0, 2.5 ≦ n ≦ 4, M is either K or Na] or (K _1-x H _x ) _y R _z Ti _2-z O ₄ .mH ₂ O [0 ≦ x <1, 0.5 ≦ y <1, m ≧ 0, R is Li, Mg, Zn, Ni, Co, Cu, Mn, Al, Fe, Cr, Any one of Ga and z has a configuration (fifth configuration) represented by z = y / 3 when R is monovalent, z = y / 2 when R is bivalent, and z = y when trivalent. Good.

  The porous titanate ion exchanger having any one of the first to fifth configurations may be configured to have a porosity of 30 to 65% (sixth configuration).

  In addition, the adsorption container according to the present invention is configured to be filled with a porous titanate ion exchanger having any one of the first to sixth configurations (seventh configuration).

  Moreover, the water treatment apparatus according to the present invention has a configuration (eighth configuration) including the adsorption container having the seventh configuration.

  According to the present invention, a porous titanate ion exchanger excellent in both strength and ion exchange performance can be provided.

Table showing examples of crystal structure of potassium titanate Table showing evaluation results of each example and comparative example Schematic diagram showing one configuration example of waste liquid treatment equipment

  Below, embodiment of the porous titanate ion exchanger which concerns on this invention is described.

The ion exchanger of the present invention comprises a layered alkali metal titanate compound having a chain structure of at least one TiO ₅ triangular bipyramid and a layered structure alkali titanate having a chain structure of at least one TiO ₆ octahedron. It consists of a metal compound

The layered structure alkali metal titanate compound having a chain structure of TiO ₅ triangular bipyramids has a weak bonding force between the negative charge on the surface of the layer and the cation between layers, and thus the swelling reaction between layers is large and the ion exchange capacity is large. It is very unstable and easily delaminates and collapses.

On the other hand, the layered structure alkali metal titanate compound having a chain structure of TiO ₆ octahedron has a strong binding force between the negative charge on the surface of the layer and the cation between layers, and is difficult to delaminate, but has a slightly low ion exchange capacity.

In an embodiment of the present invention, at least a part of secondary particles, aggregates, or granules of a layered structure alkali metal titanate compound having a chain structure of TiO ₅ triangular bipyramids, a chain structure of TiO ₆ octahedrons. By covering with an alkali metal titanate compound having a layer structure, it is possible to have sufficient strength as an ion exchanger in water without impairing excellent ion exchange performance.

Porous titanate ion exchanger of the present invention, for example, the weight B ₁ and TiO ₆ octahedra chain layered alkali metal titanate compound having a chain structure of TiO ₅ triangular bipyramidal porous titanate ion exchanger in The weight ratio B ₁ / B ₂ of the weight B ₂ of the layered structure alkali metal titanate compound having a structure is preferably 0.2 to 2.0. If B ₁ / B ₂ exceeds 2.0, the particle strength may be too low, and if B ₁ / B ₂ is below 0.2, the ion exchange performance may be too low. More preferable B ₁ / B ₂ is 0.4 to 1.2.

As the layered structure alkali metal titanate compound having a chain structure of TiO ₅ triangular bipyramids, (K _1-x H _x ) ₂ Ti ₂ O ₅ .mH ₂ O [0 ≦ x <1, m ≧ 0] ( Preference is given to potassium dititanate and / or hydrated potassium dititanate represented by the formula 1). Here, FIG. 1 shows an example of potassium dititanate having a layered structure in which a chain of TiO ₅ triangular pyramidal bodies in the case of x = 0 and m = 0 is laminated. Since a space for supporting potassium ions is formed between the interlayer portions, the cation exchange property is excellent. Further, hydrated potassium dititanate in the case of x ≠ 0 or m ≠ 0 has a similar structure, and the same effect can be obtained.

As the layered structure alkali metal titanate compound having a chain structure of TiO ₆ octahedron, (M _1-x H _x ) ₂ Ti _n O _{2n + 1} · mH ₂ O [0 ≦ x <1, m ≧ 0,2.5 ≦ n ≦ 4, M is either K or Na] (Formula 2) or (K _1−x H _x ) _y R _z Ti _2−z O ₄ .mH ₂ O [0 ≦ x <1,0. 5 ≦ y <1, m ≧ 0, R is any one of Li, Mg, Zn, Ni, Co, Cu, Mn, Al, Fe, Cr, Ga, z is z = y / 3 when R is monovalent An alkali metal titanate compound represented by z = y / 2 when divalent and z = y when trivalent (formula 3) is preferable. Here, FIG. 1 shows an example of potassium tetratitanate having a layered structure in which a chain of TiO ₆ octahedrons is stacked in Formula 2 when x = 0, m = 0, n = 4, and M is K. Show. A space for carrying potassium ions is formed between the layers. Further, hydrated potassium tetratitanate when x ≠ 0 or m ≠ 0, sodium titanate or a hydrate thereof when M in Formula 2 is Na, and a lipidocrosite type titanate compound of Formula 3 And their hydrates also have a similar layered structure, and the same effect as potassium tetratitanate can be obtained.

The compound of Formula 1, Formula 2, and x ≠ 0 in Equation 3, the compound of x = 0, respectively, protons a portion of alkali metal ^{(H +)} and / or hydronium ions _(H ^{3 O} +) Can be obtained by substituting

  Hereinafter, examples of the present invention will be described in more detail, but the present invention is not limited to the following examples. That is, with respect to the parts to which known general techniques such as various processing methods and pulverization methods described below can be applied, the contents thereof are appropriately changed without being limited to the following examples. It goes without saying that it is possible.

(Synthesis of Compound 1)
26.2 parts by weight of titanium oxide was mixed and stirred with respect to 100 parts by weight of water. Thereafter, 23.8 parts by weight of potassium carbonate was added and further stirred. The mixed solution is spray-dried at 200 ° C. (spray dry), and calcined at 800 ° C. for 3 hours to obtain a layered structure potassium dititanate (K ₂ Ti ₂ O ₅ ) having a chain structure of TiO ₅ triangular bipyramids. It was.

(Synthesis of Compound 2)
16.4 parts by weight of titanium oxide and 33.6 parts by weight of cesium carbonate are mixed by a laboratory mixer, pulverized by a ball mill, fired at 850 ° C. for 2 hours, and layered structure titanium having a chain structure of TiO ₅ triangular bipyramidal Cesium acid (Cs ₂ Ti ₂ O ₅ ) was obtained.

(Synthesis of Compound 3)
Compound 2 was added to dehydrated filter, a 3-fold amount of water relative to the weight of the compound 2 was filtered while showering, thereafter by performing a 1 hour drying at 120 ° C., TiO ₅ triangular bipyramidal Hydrated cesium dititanate (Cs _0.9 H _0.1 ) ₂ Ti ₂ O ₅ .0.1H ₂ O maintaining a layered structure having a chain structure was obtained. The composition formula was calculated from the result of composition analysis using fluorescent X-rays.

(Synthesis of Compound 4)
Compound 1 is washed with 27 times the weight of Compound 1 in water for 1 hour to depotassinate, dehydrated and dried, and then calcined at 850 ° C. for 2 hours to obtain a chain structure of TiO ₆ octahedron A layered structure of potassium tetratitanate (K ₂ Ti ₄ O ₉ ) was obtained.

(Synthesis of Compound 5)
34.3 parts by weight of titanium oxide was mixed and stirred with respect to 100 parts by weight of water. Thereafter, 15.7 parts by weight of sodium carbonate was added and further stirred. The mixed solution was spray-dried at 200 ° C. (spray dry), and calcined at 800 ° C. for 10 hours to obtain a layered structure sodium trititanate (Na ₂ Ti ₃ O ₇ ) having a chain structure of TiO ₆ octahedron.

(Synthesis of Compound 6)
The compound 5 is washed with water 7 times the weight of the compound 5 for 1 hour to remove sodium, dehydrated, and then dried at 200 ° C. for 1 hour to have a TiO ₆ octahedral chain structure. Hydrated sodium trititanate (Na _0.7 H _0.3 ) ₂ Ti ₃ O ₇ · 0.1H ₂ O maintaining the layered structure was obtained. The composition formula was calculated from the result of composition analysis using fluorescent X-rays.

(Synthesis of Compound 7)
33.9 parts by weight of titanium oxide was mixed and stirred with respect to 100 parts by weight of water. Thereafter, 16.1 parts by weight of sodium carbonate was added and further stirred. The mixed solution is spray-dried at 200 ° C. and baked at 800 ° C. for 10 hours, and a layered structure sodium trititanate (Na ₂ Ti ₃ O ₇ ) having a chain structure of TiO ₆ octahedron and pentatitanate A composite of sodium (Na ₄ Ti ₅ O ₁₂ ) was obtained.

(Synthesis of Compound 8)
33.1 parts by weight of titanium oxide was mixed and stirred with respect to 100 parts by weight of water. Thereafter, 15.2 parts by weight of potassium carbonate and 1.8 parts by weight of lithium hydroxide were added and further stirred. The mixed solution is spray-dried at 200 ° C. (spray dry), calcined at 1000 ° C. for 3 hours, and layered structure lithium potassium titanate having a chain structure of TiO ₆ octahedron (K _0.9 Li _0.3 Ti _{1. 7} O ₄ ) was obtained.

(Synthesis of Compound 9)
31.0 parts by weight of titanium oxide was mixed and stirred with respect to 100 parts by weight of water. Thereafter, 13.4 parts by weight of potassium carbonate and 5.7 parts by weight of magnesium hydroxide were added and further stirred. The mixed solution is spray-dried at 200 ° C. (spray dry), fired at 1100 ° C. for 2 hours, and layered structure magnesium potassium titanate having a chain structure of TiO ₆ octahedron (K _0.8 Mg _0.4 Ti _{1. 6} O ₄ ) was obtained.

(Synthesis of Compound 10)
The compound 9 is washed with water 5 times the weight of the compound 9 for 1 hour to remove potassium, dehydrated, and then dried at 200 ° C. for 1 hour to have a TiO ₆ octahedral chain structure. to obtain a hydrated magnesium titanate potassium maintaining the layered structure _{(K 0.7 H 0.1 Mg 0.4 Ti} 1.6 O 4 · 0.1mH 2 O). The composition formula was calculated from the result of composition analysis using fluorescent X-rays.

<Example 1>
(1-1) Adjustment of Particle Size Compound 1 and Compound 4 are prepared and adjusted so that the average secondary particle diameter of Compound 1 is ½ or less of the average secondary particle diameter of Compound 4 by grinding or crushing, respectively. did. The average secondary particle diameter of the compound 4 after adjustment is, for example, about 20 to 30 μm.

(1-2) Granulation The particle size adjusted compound 1: 460 g and the particle size adjusted compound 4: 540 g were stirred at high speed by a high speed mixing granulator (Dalton Co., Ltd., RMO-4H). Then, it granulated by stirring 370g of 5 weight% polyvinyl alcohol solutions, spraying. The obtained granulated material was baked at 850 ° C. for 2 hours in an electric muffle furnace in an air atmosphere to obtain a granulated product (porous titanate ion exchanger). The particle size of the granulated product is, for example, about 300 to 600 μm. In Examples 2 to 15 and Comparative Examples 1 to 3 described later, the particle diameter of the granulated product is, for example, about 300 to 600 μm.

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 4 having a chain structure of TiO ₆ octahedron. The ratio is 0.85, and most of the compound 1 having a relatively small particle size is present as an aggregate in the gap between the compound 4 having a relatively large particle size, and a part of the compound 1 is covered with the compound 4. It was. Moreover, the porosity of the obtained porous titanate ion exchanger was 43% by mercury porosimetry.

<Example 2>
(2-1) Particle size adjustment The particle size of Compound 1 and Compound 4 was adjusted in the same manner as in (1-1).

(2-2) Granulation Particle size adjusted compound 1: 760 g and particle size adjusted compound 4: 240 g are treated in the same step as (1-2) to obtain a granulated product (porous titanate ion exchanger). It was.

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 4 having a chain structure of TiO ₆ octahedron. The ratio was 3.16, which was the same form as that processed in the step (1-2). Moreover, the porosity of the obtained porous titanate ion exchanger was 46% by mercury porosimetry.

<Example 3>
(3-1) Particle size adjustment The particle size of Compound 1 and Compound 4 was adjusted in the same manner as in (1-1).

(3-2) Granulation Particle size adjusted compound 1: 661 g and particle size adjusted compound 4: 339 g are treated in the same step as (1-2) to obtain a granulated product (porous titanate ion exchanger). It was.

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 4 having a chain structure of TiO ₆ octahedron. The ratio was 1.95, which was the same form as that processed in the step (1-2). Moreover, the porosity of the obtained porous titanate ion exchanger was 45% by mercury porosimetry.

<Example 4>
(4-1) Particle size adjustment The particle size adjustment of the compound 1 and the compound 4 was performed similarly to (1-1).

(4-2) Granulation Particle size adjusted compound 1: 544 g and particle size adjusted compound 4: 456 g are treated in the same step as (1-2) to obtain a granulated product (porous titanate ion exchanger). It was.

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 4 having a chain structure of TiO ₆ octahedron. The ratio was 1.19, which was the same form as that processed in the step (1-2). Moreover, the porosity of the obtained porous titanate ion exchanger was 44% by mercury porosimetry.

<Example 5>
(5-1) Particle size adjustment The particle size adjustment of the compound 1 and the compound 4 was performed similarly to (1-1).

(5-2) Granulation Particle size adjusted compound 1: 304 g and particle size adjusted compound 4: 696 g are treated in the same step as (1-2) to obtain a granulated product (porous titanate ion exchanger). It was.

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 4 having a chain structure of TiO ₆ octahedron. The ratio was 0.44, which was the same form as that processed in the step (1-2). Moreover, the porosity of the obtained porous titanate ion exchanger was 42% by mercury porosimetry.

<Example 6>
(6-1) Particle Size Adjustment Compound 1 and Compound 4 were prepared and adjusted such that the average secondary particle diameter was about 20 to 30 μm, for example, by pulverization or crushing.

(6-2) Granulation Particle size adjusted compound 1: 177 g and particle size adjusted compound 4: 823 g are treated in the same step as (1-2) to obtain a granulated product (porous titanate ion exchanger). It was.

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 4 having a chain structure of TiO ₆ octahedron. The ratio was 0.21, and the relatively heavy compound 4 was partially covered with the relatively light compound 4. Moreover, the porosity of the obtained porous titanate ion exchanger was 43% by mercury porosimetry.

<Example 7>
(7-1) Particle size adjustment The particle size adjustment of the compound 1 and the compound 4 was performed similarly to (6-1).

(7-2) Granulation Particle size adjusted compound 1:84 g and particle size adjusted compound 4: 916 g are treated in the same step as (1-2) to obtain a granulated product (porous titanate ion exchanger). It was.

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 4 having a chain structure of TiO ₆ octahedron. The ratio was 0.09, which was the same form as that processed in the step (6-2). Moreover, the porosity of the obtained porous titanate ion exchanger was 44% by mercury porosimetry.

<Example 8>
(8-1) Particle Size Adjustment Compound 1 and Compound 6 were prepared and adjusted so that the average secondary particle diameter was about 20 to 30 μm, for example, by pulverization or crushing.

(8-2) Primary granulation The compound 544g adjusted in particle size was stirred at high speed with a high-speed mixing granulator (Dalton Co., Ltd., RMO-4H). Then, it granulated by stirring 200 g of 5 weight% polyvinyl alcohol solutions, spraying.

(8-3) Secondary granulation (8-2) Compound 6: 456 g adjusted in particle size was added to the total amount of the primary granulated body, and mixed with a Henschel mixer. Then, the primary granulated compound 1 was further granulated while being coated with the compound 6 by stirring while dropping 120 g of epoxy resin. The obtained secondary granulated body was fired in an electric muffle furnace in the atmosphere at 200 ° C. for 1 hour to obtain a granulated product (porous titanate ion exchanger).

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 6 having a chain structure of TiO ₆ octahedron. The ratio was 1.19, and almost the entire surface of the primary granule of Compound 1 was covered with Compound 4. The porosity of the obtained porous titanate ion exchanger was 45% by mercury porosimetry.

<Example 9>
(9-1) Particle Size Adjustment Compound 1 and Compound 8 were prepared and adjusted so that the average secondary particle diameter was about 20 to 30 μm, for example, by pulverization or crushing.

(9-2) Primary granulation The particle size-adjusted compound 1: 544 g was treated in the same step as (8-2) to obtain a primary granulated body.

(9-3) Secondary granulation (9-2) Compound 8: 456 g adjusted in particle size was added to the total amount of the primary granulated body, and mixed with a Henschel mixer. Thereafter, 170 g of a 5% by weight polyvinyl alcohol solution was added dropwise and stirred to further granulate the primary granulated compound 1 while coating with the compound 8. The obtained secondary granulated body was calcined at 850 ° C. for 2 hours in an electric muffle furnace in an air atmosphere to obtain a granulated product (porous titanate ion exchanger).

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 8 having a chain structure of TiO ₆ octahedron. The ratio was 1.19, which was the same form as that processed in the step (8-3). Moreover, the porosity of the obtained porous titanate ion exchanger was 46% by mercury porosimetry.

<Example 10>
(10-1) Particle Size Adjustment Compound 1 and Compound 10 are prepared and adjusted so that the average secondary particle diameter of Compound 1 is ½ or less of the average secondary particle diameter of Compound 10 by pulverization or crushing, respectively. did. The average secondary particle diameter of the compound 10 after adjustment is, for example, about 20 to 30 μm.

(10-2) Granulation Particle size adjusted compound 1: 544 g and particle size adjusted compound 10: 456 g were stirred at high speed by a high speed mixing granulator (Dalton Co., Ltd., RMO-4H). Then, it was granulated by stirring while spraying 300 g of epoxy resin. The obtained granulated body was fired in an electric muffle furnace in the atmosphere at 200 ° C. for 1 hour to obtain a granulated product (porous titanate ion exchanger).

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 10 having a chain structure of TiO ₆ octahedron. The ratio was 1.19, which was the same form as that processed in the step (1-2). Moreover, the porosity of the obtained porous titanate ion exchanger was 44% by mercury porosimetry.

<Example 11>
(11-1) Particle Size Adjustment Compound 3 and Compound 7 were prepared and adjusted so that the average secondary particle diameter was about 20 to 30 μm, for example, by pulverization or crushing.

(11-2) Granulation Particle size-adjusted compound 3: 177 g and particle size-adjusted compound 7: 823 g were treated in the same step as (10-2) except that the firing conditions were changed to 200 ° C. for 1 hour. A granulated product (porous titanate ion exchanger) was obtained.

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 3 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 7 having a chain structure of TiO ₆ octahedron. The ratio was 0.21, and it was the same form as that processed in the step (6-2). Moreover, the porosity of the obtained porous titanate ion exchanger was 42% by mercury porosimetry.

<Example 12>
(12-1) Particle size adjustment Compound 1 and compound 4 were adjusted in particle size in the same manner as in (1-1).

(12-2) Granulation Processed in the same process as (1-2) except that the particle size adjusted compound 1: 460 g and the particle size adjusted compound 4: 540 g were used, and 560 g of water was sprayed without using a binder. Thus, a granulated product (porous titanate ion exchanger) was obtained.

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 4 having a chain structure of TiO ₆ octahedron. The ratio was 0.85, which was the same form as that processed in the step (1-2). Further, the porosity of the obtained porous titanate ion exchanger was 70% by mercury porosimetry.

<Example 13>
(13-1) Particle size adjustment Compound 1 and compound 4 were adjusted in particle size in the same manner as in (1-1).

(13-2) Granulation The same process as (1-2) except that the particle size adjusted compound 1: 460 g and the particle size adjusted compound 4: 540 g were used and the concentration of the polyvinyl alcohol solution was changed to 3% by weight. To obtain a granulated product (porous titanate ion exchanger).

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 4 having a chain structure of TiO ₆ octahedron. The ratio was 0.85, which was the same form as that processed in the step (1-2). Moreover, the porosity of the obtained porous titanate ion exchanger was 61% by mercury porosimetry.

<Example 14>
(14-1) Particle size adjustment Compound 1 and compound 4 were adjusted in particle size in the same manner as in (1-1).

(14-2) Granulation (1-2) except that 50 g of alumina sol was added to 320 g of a 5% by weight polyvinyl alcohol solution using 460 g of particle size-adjusted compound 1: 460 g and particle-adjusted compound 4: 540 g. A granulated product (porous titanate ion exchanger) was obtained by the same process.

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 4 having a chain structure of TiO ₆ octahedron. The ratio was 0.85, which was the same form as that processed in the step (1-2). Further, the porosity of the obtained porous titanate ion exchanger was 32% by mercury porosimetry.

<Example 15>
(15-1) Particle size adjustment The particle sizes of Compound 1 and Compound 4 were adjusted in the same manner as in (1-1).

(15-2) Granulation The same process as (1-2) except that the particle size adjusted compound 1: 460 g and the particle size adjusted compound 4: 540 g were used and the concentration of the polyvinyl alcohol solution was changed to 7% by weight. A granulated product (porous titanate ion exchanger) was obtained.

The obtained porous titanate ion exchanger has a layered structure alkali metal titanate compound 1 having a TiO ₅ triangular bipyramidal chain structure with respect to a layered structure alkali metal titanate compound 4 having a chain structure of TiO ₆ octahedron. The ratio was 0.85, which was the same form as that processed in the step (1-2). Further, the porosity of the obtained porous titanate ion exchanger was 24% by mercury porosimetry.

<Comparative Example 1>
(16-1) Particle Size Adjustment Compound 1 was adjusted so that the average secondary particle diameter was, for example, about 20 to 30 μm by pulverization or crushing.

(16-2) Granulation The compound 1: 1.0 kg whose particle size was adjusted was stirred at high speed with a high-speed mixing granulator (Dalton Co., Ltd., RMO-4H). Then, it granulated by stirring 370g of 5 weight% polyvinyl alcohol solutions, spraying. The obtained granulated material was baked at 850 ° C. for 2 hours in an electric muffle furnace in an air atmosphere to obtain a granulated product (porous ion exchanger).

  The porosity of the obtained porous ion exchanger was 45% by mercury porosimetry.

<Comparative example 2>
(17-1) Particle size adjustment Compound 4 was adjusted by grinding or crushing so that the average secondary particle diameter was, for example, about 20 to 30 μm.

(17-2) Granulation The particle size-adjusted compound obtained in (16-1) 1: Except for changing 1.0 kg to the particle-size-adjusted compound 4 obtained in (17-1) (16- A granulated product (porous titanate ion exchanger) was obtained in the same step as 2).

  The porosity of the obtained porous ion exchanger was 43% by mercury porosimetry.

<Comparative Example 3>
(18-1) Particle Size Adjustment Compound 6 was adjusted so that the average secondary particle diameter was, for example, about 20 to 30 μm by pulverization or crushing.

(18-2) Granulation Granules (porous titanate ion exchanger) were obtained in the same step as (10-2): 1.0 kg of the particle size-adjusted compound 6 obtained in (18-1). .

  The porosity of the obtained porous ion exchanger was 46% by mercury porosimetry.

<Analyzer>
The analyzers used in the above examples and comparative examples are as follows.
X-ray fluorescence analyzer: Rigaku Corporation, RIX1000
Laser diffraction type particle size distribution analyzer: Shimadzu Corporation, SALD-2100
Porosity measuring device: Cantachrome Instruments, POREMASTER60

<Evaluation of ion exchange performance>
0.03 g of each porous ion exchanger obtained in Examples 1 to 15 and Comparative Examples 1 to 3 was weighed and put into each poly container (50 mL centrifuge tube). The stable isotope strontium chloride is dissolved in ion-exchanged water so that the strontium concentration is 10 mg / L, the stable isotope cesium chloride is cesium concentration is 1 mg / L, and sodium chloride is 0.3 mass%. An aqueous solution was prepared, and 30 mL of the aqueous solution was added to each plastic container. After shaking for 24 hours, solid-liquid separation was performed with a centrifuge, and the supernatant was introduced into ICP (Shimadzu Corporation, ICPE-9000) to quantify the strontium concentration after ion exchange. The ratio of the strontium concentration after ion exchange (after shaking for 24 hours) to the strontium concentration before ion exchange (before charging the plastic container) was defined as the ion exchange rate.

<Strength evaluation>
0.3 g of each porous ion exchanger obtained in Examples 1 to 15 and Comparative Examples 1 to 3 was weighed and put into each poly container (50 mL centrifuge tube). Then, after adding 30 mL of the same aqueous solution as that used for the evaluation of the ion exchange performance to each plastic container and shaking lightly, the turbidity of the supernatant is measured according to JIS K0101 (industrial water test method). Measurement was performed using Hitachi High-Technologies Corporation, U-2800). The lower the strength of the porous titanate ion exchanger, the more the porous titanate ion exchanger collapses to become fine particles and the turbidity increases. That is, there is a negative correlation between the strength and turbidity of the porous titanate ion exchanger.

<Evaluation results>
FIG. 2 is a table showing the evaluation results of Examples 1-15 and Comparative Examples 1-3. As is clear when Examples 1 to 15 and Comparative Examples 1 to 3 are compared, porous titanate ion exchangers (Examples 1 to 15) composed of a plurality of alkali metal titanates having different layered structures are composed of TiO 2. Layered structure titanic acid having a higher strength than a porous ion exchanger (Comparative Example 1) composed of a single alkali metal titanate compound having a chain structure of _five triangular bipyramids and having a chain structure of TiO ₆ octahedron The ion exchange rate is higher than that of a porous ion exchanger (Comparative Examples 2 to 3) made of an alkali metal compound alone. That is, the porous titanate ion exchanger of the present invention is excellent in both strength and ion exchange performance. The reason for this is that by mixing an alkali metal titanate compound having a layered structure with a high ion exchange performance and an alkali metal titanate compound having a strong layered structure, the particles are collapsed without significantly deteriorating the ion exchange performance. It is thought that this is because a structure that suppresses this is formed.

  Various methods can be considered for this mixing method. The simplest method is to uniformly mix an alkali metal titanate compound having a layer structure with high ion exchange performance and an alkali metal titanate compound having a layer structure with high strength in advance. And then granulating by a general method. Even this simplest method has the effect that both strength and ion exchange performance are excellent.

  However, as the structure covers more of the surface of the alkali metal titanate compound having a layered structure with high ion exchange performance, an ion exchanger with higher strength can be obtained while maintaining high ion exchange performance. As the method, the particle size of the alkali metal titanate compound having a layered structure with high ion exchange performance is adjusted to be finer than the particle size of the alkali metal titanate compound having a high-strength layered structure, and mixed in advance and granulated. Method, method of previously granulating only an alkali metal titanate compound having a layered structure with high ion exchange performance, and binding the alkali metal titanate compound having a layered structure having a high strength so as to cover the surface thereof, two layers Examples thereof include a method of obtaining a columnar granule having an alkali metal titanate compound having a layered structure with high ion exchange performance as an inner layer and an alkali metal titanate compound having a layered structure having high strength as an outer layer by an extrusion method.

  Which method is to be adopted as a mixed method may be determined in consideration of required performance and processing cost.

Considering the evaluation results of Examples 1 to 7, the weight of the layered structure alkali metal titanate compound having a chain structure of TiO ₅ triangular bipyramids relative to the layer structure structure alkali metal titanate compound having a chain structure of TiO ₆ octahedron It can be seen that the higher the ratio, the higher the Sr ion exchange rate. In addition, considering the evaluation results of turbidity, the weight of the layered structure alkali metal titanate compound having a chain structure of TiO ₅ triangular bipyramidal to the layered structure alkali metal titanate compound having a chain structure of TiO ₆ octahedron The ratio is desirably 0.2 or more and 2.0 or less, and more desirably 0.4 or more and 1.2 or less. This is because when the weight ratio of potassium tetratitanate to potassium dititanate is too low, the strength is lowered, and when the weight ratio of potassium tetratitanate to potassium dititanate is too high, the ion exchange performance is lowered.

  Considering the evaluation results of Examples 1 and 12 to 15, it is desirable that the porosity of the porous ion exchanger is 30% or more and 65% or less. This is because if the porosity is too large, the strength decreases, and if the porosity is too small, the ion exchange performance decreases.

  Although the embodiment of the present invention has been described above, the configuration of the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. That is, the above-described embodiment should be considered as illustrative in all points and not restrictive, and the technical scope of the present invention is shown by the claims, and It should be understood that all modifications that come within the meaning and range of equivalency of the claims are embraced.

For example, unless the ion exchange performance and strength are significantly reduced, the porous titanate ion exchanger according to the present invention has a layered structure alkali metal titanate compound having a chain structure of TiO ₅ triangular bipyramidal and a chain of TiO ₆ octahedrons. Substances other than the layered structure alkali metal titanate compound having a structure may be contained.

  Moreover, although the ion which the porous titanate ion exchanger which concerns on this invention exchanges is not specifically limited, when the ion exchange performance evaluation in an above-mentioned Example is considered, it can use suitably as an exchange material of a strontium ion, for example.

  The porous titanate ion exchanger according to the present invention can be used in, for example, a waste liquid treatment apparatus. Here, a configuration example of the waste liquid treatment apparatus will be described with reference to FIG. The waste liquid treatment apparatus shown in FIG. 3 has a configuration in which a plurality of columns 1 are connected in series by pipes 2. Each column 1 is filled with an ion exchanger 3 according to the present invention. Each column 1 is provided with an inlet 1A and an outlet 1B. In order to prevent the ion exchanger 3 according to the present invention from leaking out of the column 1, meshes 4 are installed at the inlet 1A and the outlet 1B. The flow of the waste liquid can be generated, for example, by providing a pump on the pipe 2 and operating the pump.

1 column 1A inflow port 1B outflow port 2 piping 3 ion exchanger according to the present invention 4 mesh

Claims (9)

A layered structure alkali metal titanate compound having a chain structure of at least one of TiO ₅ triangular bipyramidal, Ri Do a layered structure alkali metal titanate compound having at least one TiO ₆ octahedra chain structure,
Layered structure having a chain structure of TiO ₅ triangular bipyramidal layered structure in which at least a part of the surface of secondary particles, aggregates, or granules of alkali metal titanate compound has a chain structure of TiO ₆ octahedron A porous titanate ion exchanger covered with an alkali metal titanate compound . The weight ratio of the layered alkali metal titanate compound having a chain structure of the TiO ₅ triangular bipyramid to the layered alkali metal titanate compound having a chain structure of the TiO ₆ octahedron is 0.2 to 2.0. The porous titanate ion exchanger according to claim 2, wherein the porous titanate ion exchanger is present. TiO ₅ A layered structure alkali metal titanate compound having a triangular bipyramidal chain structure (K _1-x H _x ) ₂ Ti ₂ O ₅ ・ MH ₂ 3. The porous titanate ion exchanger according to claim 1, wherein the porous titanate ion exchanger is represented by O 2 [0 ≦ x <1, m ≧ 0]. TiO ₆ A layered alkali metal titanate compound having an octahedral chain structure is represented by (M _1-x H _x ) ₂ Ti _n O _{2n + 1} ・ MH ₂ O [0 ≦ x <1, m ≧ 0, 2.5 ≦ n ≦ 4, M is either K or Na] or (K _1-x H _x ) _y R _z Ti _2-z O ₄ ・ MH ₂ O [0 ≦ x <1, 0.5 ≦ y <1, m ≧ 0, R is Li, Mg, Zn, Ni, Co, Cu, Mn, Al, Fe, Cr, Ga, z is R 4 is represented by z = y / 3 when monovalent, z = y / 2 when bivalent, and z = y when trivalent. 4. Porous titanate ion exchanger. The porous titanate ion exchanger according to any one of claims 1 to 4, wherein the porosity is 30 to 65%. An adsorption container filled with the porous titanate ion exchanger according to any one of claims 1 to 5. A water treatment apparatus comprising the adsorption container according to claim 6. At least one TiO ₅ Layered structure alkali metal titanate compound having a triangular bipyramidal chain structure and at least one TiO ₆ A layered structure alkali metal titanate compound having an octahedral chain structure,
TiO ₆ Said TiO for layered structure alkali metal titanate compound having octahedral chain structure ₅ The weight ratio of the layered structure alkali metal titanate compound having a triangular bipyramidal chain structure is 0.2 to 3.2,
TiO ₅ At least a part of the surface of the secondary particle, aggregate, or granulated body of the layered structure alkali metal titanate compound having a triangular bipyramidal chain structure is the TiO ₆ A method for producing a porous titanate ion exchanger covered with a layered structure alkali metal titanate compound having an octahedral chain structure,
TiO ₅ Layered structure alkali metal titanate compound having a triangular bipyramidal chain structure, and the average diameter of secondary particles is TiO ₅ The TiO that is at least twice the average diameter of the secondary particles of the layered alkali metal titanate compound having a triangular bipyramidal chain structure ₆ A method for producing a porous titanate ion exchanger, comprising a step of stirring a layered structure alkali metal titanate compound having an octahedral chain structure. At least one TiO ₅ Layered structure alkali metal titanate compound having a triangular bipyramidal chain structure and at least one TiO ₆ A layered structure alkali metal titanate compound having an octahedral chain structure,
TiO ₆ Said TiO for layered structure alkali metal titanate compound having octahedral chain structure ₅ The weight ratio of the layered alkali metal titanate compound having a triangular bipyramidal chain structure is 0.09 to 0.21;
TiO ₅ At least a part of the surface of the secondary particle, aggregate, or granulated body of the layered structure alkali metal titanate compound having a triangular bipyramidal chain structure is the TiO ₆ A method for producing a porous titanate ion exchanger covered with a layered structure alkali metal titanate compound having an octahedral chain structure,
TiO ₅ Layered structure alkali metal titanate compound having a triangular bipyramidal chain structure, and the average diameter of secondary particles is TiO ₅ The TiO is substantially the same as the average diameter of the secondary particles of the layered structure alkali metal titanate compound having a triangular bipyramidal chain structure. ₆ A method for producing a porous titanate ion exchanger, comprising a step of stirring a layered structure alkali metal titanate compound having an octahedral chain structure.

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