KR101685801B1

KR101685801B1 - Preparation method of layered metal hydroxide

Info

Publication number: KR101685801B1
Application number: KR1020150052560A
Authority: KR
Inventors: 한양수; 이지호
Original assignee: 주식회사 세일에프에이
Priority date: 2015-04-14
Filing date: 2015-04-14
Publication date: 2016-12-13
Also published as: KR20160122534A

Abstract

The present invention relates to a process for the preparation of layered metal hydroxides having anion exchange properties. To a method for preparing a layered metal hydroxide by using a reflux method at a predetermined temperature of a transition metal precursor. Advantageously, the layered structure material can be manufactured by an economical and simple process.

Description

Preparation method of layered metal hydroxide < RTI ID = 0.0 >

The present invention relates to a process for producing a layered metal hydroxide having anion exchange properties. More particularly, the present invention relates to a method for producing a layered metal hydroxide by using a reflux method at a predetermined temperature in an aqueous solution containing a transition metal precursor, and is advantageous in that a layered structure material can be produced by a simple and economical process.

Anion exchangeable layered materials are of interest in a variety of fields and are well known for their natural mineral hydrotalcite-type compound layered double hydroxides (LDH). These compounds are two-dimensional layered structures composed of two kinds of positive ions and positively charged with negative ions exchangeable with anion-exchangeable anions. The anion layer can be exchanged with various organic / inorganic ions. By substituting various kinds of anions with these structural characteristics, it can be applied to various fields such as application of ion exchangers, catalysts, medicines and harmful anions contained in wastewater as adsorbents. The hydrotalcite-type layered metal hydrate may be prepared by a layered double metal hydroxide coprecipitation method and a hydrothermal synthesis method which is performed at a high temperature using a poorly soluble metal hydrate. For example, US Pat. No. 4,458,026 Is mixed with a metal inorganic salt and a trivalent metal inorganic salt to obtain a hydrotalcite slurry and then dried at a high temperature to prepare a hydrotalcite type catalyst. Korean Patent Registration No. 10-454273 discloses a process for producing a hydrotalcite using a polyhydric alcohol and a polyhydric alcohol ester or a metal substituent. Korean Patent Publication No. 10-601016 discloses a process for producing a hydrotalcite comprising a mixture of Mg and Al Described is a method for producing nano-sized hydrotalcite which is a layered hydroxide.

On the other hand, anion exchangeable layered materials based on a single metal cation different from the existing two kinds of cationic LDHs have been developed and reported in the academic world (Solid State Ionics 53-56 (1992) 527-533). In this paper, the method and properties of synthesizing an anion-exchangeable layered structure material of botallackite-type using copper acetate monohydrate and precipitant were described.

The hydrotalcite form and the anthanquat form of anion exchangeable compounds described in the above document are usually composed of a basic precipitant, the use of chemicals in the separation and washing process, and a complicated process, A method is required.

The present inventors have completed and improved the above-mentioned problems of the prior art to provide a simplified synthesis method of a layered metal hydroxide having anion exchange property.

In the present invention, a method for producing a layered hydroxide having anion exchange property is composed of the following single steps. M ₂ having a layered structure by hydrolysis method to produce an aqueous solution of a metal salt compound, and allowed to warm _{(OH) 3 (X) ·} nH 2 O (M = Ca, Mg, Mn, Fe, Co, Ni, Cu, Zn, X _{^{_{= CH 3 COO -, NO 3}}} -, Cl -, SO 4 -, HClO -, consists of the steps of synthesizing alpha-hydroxy acid salts, fatty acid salts, alkyl sulfates, alkyl seulpon acid) materials, such as citric acid.

First, the corresponding transition metal salt is used as a starting material for the synthesis of a layered metal hydroxide (M ₂ (OH) ₃ (X) .nH ₂ O). A metal aqueous solution prepared by dissolving these transition metal hydrates in distilled water is prepared and a precipitation reaction is induced by a hydrolysis reaction using the reflux method. At this time, the temperature of the solution for hydrolysis is adjusted within the range of 50 to 150 ° C. When the temperature is 50 ° C or lower, the basic layered compound by hydrolysis is not effectively achieved, and when the temperature is 150 ° C or higher, the hydrolysis proceeds excessively, and metal oxide-type impurities may be formed. The pH of the hydrolysis reaction is not particularly limited, but is preferably in the range of 5 to 9. After completion of the hydrolysis reaction, separation and washing are carried out to obtain a powdery metal hydroxide (M ₂ (OH) ₃ (X) .nH ₂ O) in a layered structure. Formation of a layered compound can be easily confirmed by using X-ray diffraction (XRD).

The above results show that the layered metal hydroxide can be easily synthesized by using the reflux method without using any precipitant, so that the object of the present invention can be achieved.

Through the present invention, it is possible to simplify the complicated manufacturing process of the layered metal hydroxide having the conventional anion exchange property into a single process, and economical effect can be obtained through the process. The obtained layered metal hydroxide has various kinds of anions The present invention can be applied to various fields such as functional composite materials, catalysts, medicines, and application of harmful anions contained in wastewater as adsorbents.

1. X-ray diffraction analysis of Cu ₂ (OH) ₃ (CH ₃ COO) .H ₂ O prepared in Example 1
2. Scanning electron microscope (FE-SEM) analysis results of Cu ₂ (OH) ₃ (CH ₃ COO) .H ₂ O prepared in Example 1
3. X-ray diffraction analysis of the layered metal hydroxide in which the sodium dodecyl sulfate of Example 3 was intercalated

A specific example of the present invention is presented through examples. However, the following examples are intended to illustrate specific examples of the invention, but the scope of the present invention should not be construed as being limited by the examples.

Example 1

For the preparation of layered copper hydroxide, copper acetate (Cu (CH ₃ COO) ₂ ) was _first dissolved in distilled water to prepare 100 mL of 0.2 M aqueous copper acetate solution. The temperature of the solution was raised to 80 DEG C and the hydrolysis reaction was carried out while refluxing for 2 hours. When the hydrolysis reaction was completed, solid-liquid separation was carried out by centrifugation, and the reaction mixture was washed with water three times to remove unreacted materials and impurities. The precipitate thus obtained was dried at 100 ° C for 2 hours to prepare a layered copper hydroxide, Cu ₂ (OH) ₃ (CH ₃ COO) .H ₂ O. Formation of the layered copper hydroxide was confirmed by a unique XRD diffraction pattern having an interlayer distance of 9.3 Å as shown in FIG. Figure 2 shows the results of scanning electron microscopy (FE-SEM) observation of the synthesized layered copper hydroxide. The synthesized layered metal hydroxide has a plate-like shape and the size of the particles is 1 ~ 10μm.

Example 2

Example 1 using acetate cobalt _{(Co (CH 3 COO) 2} ) in place of copper metal precursor of acid in and the rest in the same way as carried out stratified cobalt _{hydroxide, Co 2 (OH) 3 (} CH 3 COO) · H 2 O, < / RTI > As a result of X-ray diffraction analysis, Co ₂ (OH) ₃ (CH ₃ COO) .H ₂ O compound having an interlayer distance of 9.5 Å was produced.

Example 3

Sodium Dodecyl Sulfate (SDS), which is a kind of anionic surfactant, was added between the layers of the layered copper hydroxide (Cu ₂ (OH) ₃ (CH ₃ COO) .H ₂ O) obtained through the synthesis process of Example 1, Was carried out. 200 mg of Cu ₂ (OH) ₃ (CH ₃ COO) .H ₂ O synthesized in Example 1 was added to 50 mL of distilled water, and the mixture was redispersed by stirring for 1 hour. 50 ml of a 0.17 M SDS aqueous solution was added thereto, followed by ion exchange reaction with stirring. The ion exchange reaction was carried out at 30 DEG C for 24 hours. After the ion exchange reaction was completed, solid-liquid separation was performed by centrifugation, washed once with ethanol, and washed twice with distilled water to remove unreacted materials and impurities. The ion exchange reactant thus obtained was dried at 100 ° C for 2 hours to prepare a layered copper hydroxide, Cu ₂ (OH) ₃ (SDS), intercalated between SDS layers. When the SDS ions were exchanged, the interlayer distance increased to 27.8 Å as shown in FIG. 3, which means that SDS ions were inserted between the copper hydroxide layer lattices.

Claims

The transition metal hydrate is dissolved in distilled water and a precipitation reaction by a hydrolysis reaction is induced in a temperature range of 50 to 150 ° C by refluxing without using a separate precipitant to obtain M ₂ (OH) ₃ (X ) &Lt; / _RTI > nH2O.
The metal M includes at least one selected from Ca ²⁺ , Mg ²⁺ , Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ and Zn ²⁺ ;
The interlayer anions X are _{^{CH 3 COO -, HCOO -,}} NO 3 -, Cl -, HClO -, SO 4 2-, CO 3 2-, citrate, oxalate, tartrate, fatty acid salts, will be selected from alkyl sulfate ;
The crystal number n is in the range of 0 to 2.

delete

The method according to claim 1, wherein the interlayer distance by X-ray analysis of the layered metal hydroxide is 6 to 50 Å.