JPH05229900A - Production of phombic layered titanic acid plate crystal represented by hxmyti2-yo4-nh2o - Google Patents

Abstract

PURPOSE:To produce new rhombic layered titanic acid plate crystal represented by HxMyTi2-yO4.nH2O. CONSTITUTION:The objective rhombic layered titanic acid plate crystal represented by a general formula HxMyTi2-yO4.nH2O (Provided that M shows Mg<2+>, Ni<2+>, Zn<2+>, Cu<2+>, Fe<3+>, Al<3+>, Ga<3+> or Mn<3+>, (x) and (y) are respectively within a range of 0.5 to 1.0 and of 0.25 to 1.0. (n) is <=2) is obtained by treating a rhombic layered plate crystal expressed by a general formula AxMyTi2-yO4 (Provided that A shows K, Rb or Cs. M is Mg<2+>, Ni<2+>, Zn<2+>, Cu<2+>, Fe<3+>, Al<3+>, Ga<3+> or Mn<3+>. (x) and (y) are respectively within a range of 0.5 to 1.0 and of 0.25 to 1.0) with an acid aqueous solution so as to exchange A ion coordinated between the layers with H<+> ion or H3O<+> ion. As the aqueous acid solution for extracting A ion by acid treatment, any aqueous acid solution may be used and an aqueous hydrochloric acid solution is most suitable. The plate crystal is useful as a cation exchanger, a filter, a proton conductor and a catalyst.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the general formula AxMyTi ₂ _yO.
₄ (However, A is K, Rb or Cs, M is Mg ² +, Ni ² +, Zn
^{2 +, Cu 2 +, Fe} 3 +, Al 3 +, represents Ga ³ + or Mn ³ +,
x is in the range of 0.5 to 1.0 and y is in the range of 0.25 to 1.0. Hereinafter the same), from a plate crystal having an orthorhombic layered structure, the general formula HxMyTi ₂ _yO ₄ .nH ₂ O (where M is Mg ²
+, Ni ² +, Zn ² +, Cu ² +, Fe ³ +, Al ³ +, Ga ³ + or Mn
³ +, x is in the range of 0.5 to 1.0, y is in the range of 0.25 to 1.0, and n is 2 or less, and the same shall apply hereinafter). Concerning the law. The plate crystals are useful as a cation exchanger, a filter, a proton conductor and a catalyst.

[0002]

2. Description of the Related Art Generally,
Titanic acid is represented by TiO ₂ .nH ₂ O, and is an amorphous gel substance. This is known as a unique inorganic ion adsorbent and is widely used as a material for recovering uranium in seawater. However, since it is not a crystal, it is difficult to control the selectivity of metal ions.

The object of the invention is the general formula HxMyTi ₂ _yO ₄
· NH is to provide a method for producing titanate of plate crystals having an orthorhombic layer structure represented by ₂ O.

[0004]

The tabular crystalline titanic acid obtained in the present invention has a composition represented by the general formula HxMyTi ₂ —yO ₄ .nH ₂ O and has a layered structure. The TiO ₆ octahedrons are chained to share a common edge plane to form a layered structure. Since part of the Ti seat is replaced with M metal ions, H ions or H ₃ O ions can be stably coordinated between the layers for adjusting the positive charge.

At the beginning, this type of titanic acid cannot be synthesized, but as an initial phase, a plate-like crystal having an orthorhombic layered structure represented by the general formula AxMyTi ₂ _yO ₄ was synthesized, which was secondarily synthesized. by exchanging the a ions and H + ions or H ₃ O + ions to the acid treatment, manufacturing titanate of plate crystals having a layered structure of orthorhombic represented by HxMyTi ₂ _yO ₄ · nH ₂ O I was determined to be done. It is a substance that can be produced only by this process.

As the acid aqueous solution for extracting the A ions by the acid treatment, any acid aqueous solution may be used, but hydrochloric acid aqueous solution is most effective. The acid concentration and the treatment time are important conditions, but this also has a large effect on the crystallinity of the synthesized crystals, and the higher the crystallinity, the longer the time required for the same concentration. Also, the processing time can be determined appropriately, keeping in mind that the processing time is greatly affected.

Further, the general formula AxMyTi ₂ as a starting material is used.
As a method for synthesizing the plate crystal having an orthorhombic layered structure represented by _yO ₄ , a suitable method such as a flux method may be used.

Next, examples of the present invention will be described.

[0009]

EXAMPLE First, KxMgyTi ₂ _yO ₄ (x
= 0.8, y = 0.4) was synthesized.
This synthesis was performed by the flux method. _{(K 2 O) 0. 5} (Mg
O) _{0. 5} (a TiO _{2) 1. 5} molar ratio ratio of crystal raw material powder, (K
_{2 O) 1. 0 (MoO} 3) 1. The molar ratio proportion of flux material powder ₀ were mixed at a ratio of molar percentage of 30 to 70.

A platinum crucible was filled with this mixture, melted at 1150 ° C. in an electric furnace, and then gradually cooled to 950 ° C. at a rate of 4 ° C./h to grow a crystal. After the gradual cooling, the crucible was taken out and allowed to cool in the atmosphere. The produced crystals were immersed in boiling water together with the crucible to dissolve the flux and then taken out. Two
Plate-like crystals having a diamond shape of ˜3 mm × 3-5 mm were obtained.
This plate crystal was identified by an X-ray powder diffraction method,
It was a good crystal of the target substance.

This plate crystal was crushed to about 0.5 mm, immersed in 1 liter of an aqueous 0.1N HCl solution per 2 g, and subjected to K ion extraction for 5 hours with stirring to exchange it with H + ion. It was After the reaction, the product was washed with water and placed in a container to prevent drying, and used as an ion exchange agent.

For identification, the sample was dried and kept at 500 ° C.
When it is heat-treated at 60 ° C, it becomes anatase, and when it is baked at 1000 ° C, it becomes rutile, so all K ions are H +.
Substituted with ions, H _{0. 8} Mg _0. It was found to be ₄ Ti _{1. 6} titanate O ₄ · nH ₂ O composition.

[0013]

As described above, according to the present invention,
Titanium plate-like crystals, while retaining the layer structure of orthorhombic, represented by the general formula HxMyTi _{2 _yO 4} · nH ₂ O having a layered structure of orthorhombic represented by the general formula AxMyTi ₂ _yO ₄ Plate-like crystals of acid can be produced. This plate crystal is useful as a cation exchanger, a filter, a proton conductor and a catalyst.

Claims (1)

[Claims] 1. A general formula AxMyTi ₂ _yO ₄ (where A is K, Rb or Cs, M is Mg ² +, Ni ² +, Zn ² +, Cu ² +, F
e ³ +, Al ³ +, Ga ³ + or Mn ³ +, and x is 0.5 to 1.
0, y is the layered platelets orthorhombic indicated by a is) the range of 0.25 to 1.0, by processing the A ions coordinated to the interlayer with aqueous acid H + or H ₃ O + by exchanging the ions, formula _{HxMyTi 2 _yO 4 · nH 2 O} ( where, M
The ^{Mg 2 +, Ni 2 +,} Zn 2 +, Cu 2 +, Fe 3 +, Al 3 +, Ga 3 +
Or Mn ³ +, x is 0.5 to 1.0, y is 0.25 to
In the range of 1.0, n is 2 or less.) The method for producing an orthorhombic layered titanic acid plate crystal.