Adsorbent material and method for producing crystalline silicotitanate

Patent metadata

Field	Value
Publication number	US-9675957-B2
Application number	US-201615284020-A
Country	US
Kind code	B2
Filing date	Oct 3, 2016
Priority date	Mar 27, 2014
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

There are provided an adsorbent material excellent in the adsorptive removal properties of Cs and Sr also in seawater, and a method for producing a crystalline silicotitanate suitable for the adsorbent material.
The adsorbent material according to the present invention comprises: at least one selected from crystalline silicotitanates represented by Na 4 Ti 4 Si 3 O 16 .nH 2 O, (Na x K (1-x) ) 4 Ti 4 Si 3 O 16 .nH 2 O and K 4 Ti 4 Si 3 O 16 .nH 2 O wherein x represents a number of more than 0 and less than 1 and n represents a number of 0 to 8; and at least one selected from titanate salts represented by Na 4 Ti 9 O 20 .mH 2 O, (Na y K (1-y) ) 4 Ti 9 O 20 .mH 2 O and K 4 Ti 9 O 20 .mH 2 O wherein y represents a number of more than 0 and less than 1 and m represents a number of 0 to 10. The adsorbent material is suitably produced by a method for producing a crystalline silicotitanate in which a silicic acid source, a sodium compound and/or a potassium compound, titanium tetrachloride, and water are mixed to obtain a mixed gel, and the mixed gel is subjected to a hydrothermal reaction.

First claim

What is claimed is:

1. A method for producing at least one crystalline silicotitanate selected from crystalline silicotitanates represented by the general formulae: Na 4 Ti 4 Si 3 O 16 .nH 2 O, (Na x K (1-x) ) 4 Ti 4 Si 3 O 16 .nH 2 O and K 4 Ti 4 Si 3 O 16 .nH 2 O wherein x represents a number of more than 0 and less than 1 and n represents a number of 0 to 8, the method comprising:
a first step of mixing a silicic acid source, a sodium compound and/or a potassium compound, titanium tetrachloride and water to thereby obtain a mixed gel; and
a second step of subjecting the mixed gel obtained in the first step to a hydrothermal reaction,
wherein in the first step, the silicic acid source and the titanium tetrachloride are added so that a molar ratio of Ti and Si contained in the mixed gel becomes Ti/Si=0.5 or higher and 3.0 or lower.

2. The method for producing a crystalline silicotitanate according to claim 1 , comprising by-producing at least one selected from titanate salts represented by the general formulae: Na 4 Ti 9 O 20 .nH 2 O, (Na y K (1-y) ) 4 Ti 9 O 2 .mH 2 O and K 4 Ti 9 O 20 .mH 2 O wherein y represents a number of more than 0 and less than 1 and m represents a number of 0 to 10.

3. The method for producing a crystalline silicotitanate according to claim 1 , comprising using a sodium compound and a potassium compound in the first step to thereby obtain a crystalline silicotitanate comprising Na 4 Ti 4 Si 3 O 16 .nH 2 O and K 4 Ti 4 Si 3 O 16 .nH 2 O, or (Na x K (1-x) ) 4 Ti 4 Si 3 O 16 .nH 2 O.

4. The method for producing a crystalline silicotitanate according to claim 1 , wherein in the first step, the silicic acid source is soda silicate, or an active silicic acid obtained by cationically exchanging an alkali silicate.

5. The method for producing a crystalline silicotitanate according to claim 4 , wherein in the first step, the silicic acid source is soda silicate; and a mixture of the soda silicate and a sodium compound and/or a potassium compound, and titanium tetrachloride are mixed to thereby obtain the mixed gel.

6. The method for producing a crystalline silicotitanate according to claim 4 , wherein in the first step, the silicic acid source is an active silicic acid obtained by cationically exchanging an alkali silicate; and a mixture of the active silicic acid and titanium tetrachloride, and a sodium compound and/or a potassium compound are mixed to thereby obtain the mixed gel.

7. The method for producing a crystalline silicotitanate according to claim 1 , wherein in the first step, the sodium compound and/or the potassium compound is added so that a total concentration in terms of Na 2 O of sodium and potassium in the mixed gel becomes 0.5% by mass or higher and 15% by mass or lower.

8. The method for producing a crystalline silicotitanate according to claim 7 , wherein in the first step, the silicic acid source is soda silicate; and the sodium compound and/or the potassium compound is added so that the total concentration in terms of A′ 2 O of sodium and potassium in the mixed gel becomes 2.8% by mass or higher and 4.5% by mass or lower, wherein A′ represents Na and K.

9. The method for producing a crystalline silicotitanate according to claim 7 , wherein in the first step, the silicic acid source is an active silicic acid obtained by cationically exchanging an alkali silicate; and the sodium compound and/or the potassium compound is added so that the total concentration in terms of A′ 2 O of sodium and potassium in the mixed gel becomes 1% by mass or higher and 6% by mass or lower, wherein A′ represents Na and K.

10. The method for producing a crystalline silicotitanate according to claim 1 , wherein in the first step, a total concentration of a silicic acid source concentration in terms of SiO 2 and a titanium tetrachloride concentration in terms of TiO 2 in the mixed gel is 2.0% by mass or higher and 40% by mass or lower; and the silicic acid source and the titanium tetrachloride are added so that a molar ratio of A′ 2 O and SiO 2 in the mixed gel becomes A′ 2 O/SiO 2 =0.5 or higher and 3.0 or lower, wherein A′ represents Na and K.

11. The method for producing a crystalline silicotitanate according to claim 1 , wherein in the first step, the sodium compound and the potassium compound are hydroxides.

12. The method for producing a crystalline silicotitanate according to claim 1 , wherein the crystalline silicotitanate in a hydrous state obtained by the hydrothermal reaction in the second step is dried to thereby obtain a dried material, and the dried material is disintegrated or ground.

13. The method for producing a crystalline silicotitanate according to claim 1 , wherein the crystalline silicotitanate in a hydrous state obtained by the hydrothermal reaction in the second step is extruded through a hole member having a plurality of holes formed therein to thereby obtain a rod-form molded body, and the obtained rod-form molded body is dried.

14. The method for producing a crystalline silicotitanate according to claim 13 , wherein the rod-form molded body is dried to thereby obtain a dried molded body, and the dried molded body is disintegrated or ground.

Assignees

• Nippon Chemical Ind

Inventors

• Miyabe Shinsuke
• Kinose Yutaka
• Kikuchi Masahiro
• Sakamoto Takeshi

Classifications

• C01B33/32

  Alkali metal silicates ({C01B33/24} , C01B33/26 take precedence) · CPC title

• B01J20/30

  Processes for preparing, regenerating, or reactivating · CPC title

• B01J20/3085

  Chemical treatments not covered by groups B01J20/3007 - B01J20/3078 · CPC title

• C01G23/005

  Alkali titanates · CPC title

• B01J20/3021

  Milling, crushing or grinding · CPC title