Layered double hydroxide crystal, anion adsorbent, and method for producing layered double hydroxide crystal

Patent metadata

Field	Value
Publication number	US-12492135-B2
Application number	US-202017633682-A
Country	US
Kind code	B2
Filing date	Aug 20, 2020
Priority date	Aug 23, 2019
Publication date	Dec 9, 2025
Grant date	Dec 9, 2025

Abstract

What is provided is a layered double hydroxide crystal for achieving higher ion-exchange capacity than that of the related art.The layered double hydroxide crystal 1 according to the present embodiment is represented by Formula (1) and composed of a plurality of crystal grains 10 each of which has a lamination structure in which a plurality of plate-shaped crystals (11), (11), . . . are laminated, in which particle sizes of the plurality of crystal grains (10), (10), . . . are uniform on a microscale. [Ni2+1−xFe3+x(OH)2]·[(Cl−)X/2]  (1) (Where, 0.25<x≤0.9)

First claim

What is claimed is:

1 . A layered double hydroxide crystal represented by Formula (1) comprising:
a plurality of crystal grains, wherein each of the plurality of crystal grains has a lamination structure in which a plurality of plate-shaped crystals are laminated, and particle sizes of the plurality of crystal grains are uniform on a microscale, each of the particle sizes of the plurality of crystal grains is distributed in a range of 0.1 μm to 20 μm, and a relative particle amount q 3 shows the maximum value in a range of the particle size of 4 μm to 4.8 μm,
[Ni 2+ 1−x Fe 3+ x (OH) 2 ]·[(Cl − ) X/2 ]  (1),

where, 0.25<x≤0.9.

2 . The layered double hydroxide crystal according to claim 1 , wherein
an interlayer space is formed between adjacent plate-shaped crystals, and the plurality of plate-shaped crystals and a plurality of the interlayer spaces are alternately arranged.

3 . An anion adsorbent comprising the layered double hydroxide crystal according to claim 1 .

4 . The anion adsorbent according to claim 3 , wherein
the anion adsorbent adsorbs one or two or more kinds of anions selected from the group consisting of fluoride ions, sulfate ions, and arsenide ions.

5 . A method for producing the layered double hydroxide crystal of claim 1 comprising:
A step of preparing, as a raw material, a mixture of a Ni source substance, a Fe source substance, and a Na source substance which are mixed based on a precursor crystal stoichiometric proportion;
A step of heating the raw material at 600° C. to 1000° C. for 1 hour or longer to produce precursor crystals composed of NaNi 1−x Fe x O 2 crystals (0.25<x≤0.9);
A step of hydrolyzing the precursor crystals;
A step of carrying out a reduction treatment on crystals obtained by the hydrolysis of the precursor crystals; and
A step of substituting a carbonate ion positioned on an interlayer between the crystals obtained by the reduction treatment with a chloride ion.

Assignees

• Univ Shinshu

Inventors

• Teshima Katsuya
• Sudare Tomohito

Classifications

• C30B9/04

  by cooling of the solution · CPC title

• C02F2101/12

  Halogens or halogen-containing compounds · CPC title

• C02F2101/103

  Arsenic compounds · CPC title

• C02F2101/101

  Sulfur compounds · CPC title

• B01J41/10 Primary

  Inorganic material · CPC title