阅读说明：本技术 一种CuMgAl层状氧化物及其制备方法和用途 (CuMgAl layered oxide and preparation method and application thereof ) 是由 闫方友 贾青竹 张鸿敏 于 2019-09-20 设计创作，主要内容包括：本发明实施例涉及一种CuMgAl层状氧化物及其制备方法和用途,所述CuMgAl层状氧化物用于活化过硫酸盐,其制备方法包括如下步骤：将含有Cu<Sup>2+</Sup>的可溶性铜盐、含有Mg<Sup>2+</Sup>的可溶性镁盐和含有Al<Sup>3+</Sup>的可溶性铝盐溶于水中,制备第一混合溶液；将NaOH和Na<Sub>2</Sub>CO<Sub>3</Sub>溶于水中,制备第二混合溶液；在搅拌条件下,将第一混合溶液和第二混合溶液同时滴加至一定体积的水中,在滴加过程中保持反应体系的pH值稳定,滴加完毕后,对所获得的混合物经处理步骤获得CuMgAl层状氢氧化物,所述pH值的取值范围为8-9；对所述CuMgAl层状氢氧化物进行煅烧处理。该方法制备的CuMgAl层状氧化物能够用于活化过硫酸盐。(The embodiment of the invention relates to a CuMgAl layered oxide, a preparation method and application thereof, wherein the CuMgAl layered oxide is used for activating persulfate, and the preparation method comprises the following steps: will contain Cu 2+ Soluble copper salt of (2) containing Mg 2+ Soluble magnesium salt of (5) and containing Al 3+ Dissolving the soluble aluminum salt in water to prepare a first mixed solution; mixing NaOH and Na 2 CO 3 Dissolving in water to prepare a second mixed solution; under the condition of stirring, simultaneously dripping the first mixed solution and the second mixed solution into water with a certain volume, keeping the pH value of a reaction system stable in the dripping process, and after finishing dripping, carrying out treatment on the obtained mixture to obtain CuMgAl layered hydroxide, wherein the value range of the pH value is 8-9; and calcining the CuMgAl layered hydroxide.The CuMgAl layered oxide prepared by the method can be used for activating persulfate.)

1. A method for producing a CuMgAl layered oxide for activating a persulfate, comprising the steps of:

will contain Cu²⁺Soluble copper salt of (2) containing Mg²⁺Soluble magnesium salt of (5) and containing Al³⁺Dissolving the soluble aluminum salt in water to prepare a first mixed solution;

NaOH and Na₂CO₃Dissolving in water to prepare a second mixed solution;

under the condition of stirring, simultaneously dropwise adding the first mixed solution and the second mixed solution into a certain volume of water, keeping the pH value of the reaction system stable in the dropwise adding process, and after the dropwise adding is finished, processing the obtained mixture to obtain CuMgAl layered hydroxide, wherein the value range of the pH value is 8-9;

-subjecting said CuMgAl layered hydroxide to a calcination treatment.

2. The method of claim 1, wherein the Cu is present²⁺The soluble copper salt of (A) is Cu (NO)₃)₂·3H₂O and/or Cu (NO)₃)₂(ii) a Said containing Mg²⁺The soluble magnesium salt is MgSO₄·7H₂O and/or MgSO₄And/or Mg (NO)₃)₂·6H₂O and/or Mg (NO)₃)₂(ii) a Said Al-containing component³⁺The soluble aluminum salt of (2) is Al (NO)₃)₃·9H₂O and/or Al (NO)₃)₃。

3. The method of claim 1 or 2, wherein in the first mixed solution, Cu²⁺、Mg²⁺、Al³⁺The molar ratio of (1-4) to (3: 2).

4. The method of claim 3, wherein in the first mixed solution, Cu²⁺、Mg²⁺、Al³⁺The molar ratio of (A) to (B) is 3: 2.

5. The method of claim 1 or 2, wherein Cu²⁺Has a molar concentration of 0.15mol/L and Mg²⁺Has a molar concentration of 0.15mol/L and Al³⁺The molar concentration of (A) is 0.1 mol/L.

6. The method of claim 1 or 3, wherein NaOH and Na are present in the second mixed solution₂CO₃The molar ratio of (1-3) to 1.

7. The method of claim 6, wherein the molar concentration of NaOH is 1-3mol/L, Na₂CO₃The molar concentration of (a) is 1 mol/L.

8. The method according to claim 1, wherein the treating step comprises an aging step in which an aging temperature is 50 ℃, a washing step, and a drying step; in the drying step, the drying temperature is 80 ℃, and the drying time is 12 hours; in the calcination treatment, the calcination temperature is 500 ℃ and the calcination time is 5 h.

9. CuMgAl layered oxide for activating persulfates, characterized in that it is prepared using the preparation method according to one of claims 1 to 8.

10. Use of a CuMgAl layered oxide prepared by the preparation method according to one of claims 1 to 8 for activating persulfates.

Technical Field

The invention belongs to the technical field of catalysts, and particularly relates to a CuMgAl layered oxide, and a preparation method and application thereof.

Background

The persulfate advanced oxidation technology is sulfate radical SO₄ ^-Is an advanced oxidation technology for oxidizing macromolecular refractory organic matters into low-toxicity or non-toxic micromolecular substances for main active substances. In recent years, the technology is widely applied to the field of environmental pollution treatment, such as in-situ remediation of groundwater and the environment. The sulfate radical SO can be obtained by activating persulfate₄ ^-。

At present, the methods for activating persulfate mainly comprise metal ion activation, natural mineral activation, thermal activation and the like. The metal ion activation is easy to generate secondary pollution, natural minerals are limited in practical application due to insufficient concentration of effective components, and energy and cost required by thermal activation are high. Therefore, the research on high-efficiency catalysts for activating persulfates is an important direction of the advanced oxidation technology of persulfates.

Hydrotalcite-like substances are inorganic materials with a layered structure, interlayer water molecules, hydroxyl ions and other anions are lost through high-temperature calcination, and layered oxides (LDO) with high specific surface area are obtained.

The persulfate advanced oxidation technology has a good effect of removing organic pollutants, such as medicines, insecticides, halogenated compounds, organic dyes and the like. Taking organic dyes as an example, such organic pollutants are widely used not only in textile, printing, tanning and coating industries, but also in food technology and agricultural research, most of the organic dyes are dissolved in water in an ionic form, and pose a serious threat to human health due to their toxicity and non-biodegradability, and groundwater is polluted by such pollutants. However, the prior art lacks a catalyst for activating persulfate with high efficiency.

Disclosure of Invention

In order to solve the technical problems, the invention provides a CuMgAl layered oxide and a preparation method and application thereof.

According to a first aspect of the invention, the embodiment of the invention provides a preparation method of a CuMgAl layered oxide.

<1> a method for preparing a CuMgAl layered oxide for activating persulfate, comprising the steps of:

will contain Cu²⁺Soluble copper salt of (2) containing Mg²⁺Soluble magnesium salt of (5) and containing Al³⁺Dissolving the soluble aluminum salt in water to prepare a first mixed solution;

NaOH and Na₂CO₃Dissolving in water to prepare a second mixed solution;

under the condition of stirring, simultaneously dropwise adding the first mixed solution and the second mixed solution into a certain volume of water, keeping the pH value of the reaction system stable in the dropwise adding process, and after the dropwise adding is finished, processing the obtained mixture to obtain CuMgAl layered hydroxide, wherein the value range of the pH value is 8-9;

-subjecting said CuMgAl layered hydroxide to a calcination treatment.

<2>Such as<1>The method of, the Cu-containing²⁺The soluble copper salt of (A) is Cu (NO)₃)₂·3H₂O and/or Cu (NO)₃)₂(ii) a Said containing Mg²⁺The soluble magnesium salt is MgSO₄·7H₂O and/or MgSO₄And/or Mg (NO)₃)₂·6H₂O and/or Mg (NO)₃)₂(ii) a Said Al-containing component³⁺The soluble aluminum salt of (2) is Al (NO)₃)₃·9H₂O and/or Al (NO)₃)₃。

<3>Such as<1>Or<2>The method, the first mixed solution, Cu²⁺、Mg²⁺、Al³⁺The molar ratio of (1-4) to (3: 2).

<4>Such as<3>The method, the first mixed solution, Cu²⁺、Mg²⁺、Al³⁺The molar ratio of (A) to (B) is 3: 2.

<5>Such as<1>Or<2>Said method, Cu²⁺Has a molar concentration of 0.15mol/L and Mg²⁺Has a molar concentration of 0.15mol/L and Al³⁺The molar concentration of (A) is 0.1 mol/L.

<6>Such as<1>Or<3>The method, the second mixed solution, NaOH and Na₂CO₃The molar ratio of (1-3) to 1.

<7>Such as<6>In the method, the molar concentration of NaOH is 1-3mol/L, and Na is added₂CO₃The molar concentration of (a) is 1 mol/L.

<8> the method as stated in <1>, the treating step includes an aging step in which an aging temperature is 50 ℃, a washing step, and a drying step; in the drying step, the drying temperature is 80 ℃, and the drying time is 12 hours; in the calcination treatment, the calcination temperature is 500 ℃ and the calcination time is 5 h.

According to a second aspect of the present invention, embodiments of the present invention also provide a CuMgAl layered oxide.

<9> a CuMgAl layered oxide for activating a persulfate, which is prepared using the preparation method as stated in one of <1> to <8 >.

According to a third aspect of the invention, the embodiment of the invention also provides the application of the CuMgAl layered oxide.

<10> use of the CuMgAl layered oxide prepared by the preparation method as described in any one of <1> to <8> for activating persulfate.

The embodiment of the invention has the following beneficial effects: according to the preparation method of the CuMgAl layered oxide for activating the persulfate, provided by the embodiment of the invention, the salt solution and the alkali solution are simultaneously dripped into water for mixing reaction under the condition of keeping the pH value stable (the pH value ranges from 8 to 9, namely the pH value is a certain pH value between 8 and 9, and the pH value is 8 and 9), so that the CuMgAl layered oxide suitable for activating the persulfate can be prepared, and the CuMgAl layered oxide can be used for activating the persulfate to treat organic pollutants.

Drawings

Fig. 1 is an X-ray diffraction chart of the layered oxide obtained in the first to fourth embodiments and the first comparative example in example 1 of the present invention.

Fig. 2 is a graph showing the change of the SMD concentration removal rate with time in the SMD experiment in the treated water using the layered oxides prepared using different molar ratios of metal ions as catalysts in the first to fourth embodiments and the first comparative example of example 1 of the present invention.

Fig. 3 is an infrared spectrum of the CuMgAl layered oxide obtained in the sixth embodiment of example 1 of the present invention and the CuMgAl layered oxide after repeated use.

Fig. 4 is a graph showing the change of the SMD concentration removal rate with time in the SMD experiment in the treated water using the layered oxides prepared with different alkali liquor ratios as the catalyst in the third, fifth, and seventh embodiments of the present invention in example 1.

Fig. 5 is an SEM image of the layered oxide obtained in the sixth embodiment in example 1 of the present invention.

Fig. 6 is a graph showing the change of the SMD concentration removal rate with time in the SMD experiment in the treated water using the layered oxides prepared at different pH values as the catalyst in the third and seventh embodiments of the present invention in example 1.

FIG. 7 is a graph showing the SD concentration removal rate in different systems with time in SD experiments on treated water of the catalysts obtained in the sixth embodiment of example 1 of the present invention, the first comparative example and the second comparative example 2 of the present invention.

FIG. 8 is a graph showing the SD concentration removal rate with time for different catalyst addition amounts in an SD experiment in treated water using the layered oxide obtained in the sixth embodiment of example 1 of the present invention as a catalyst.

FIG. 9 is a graph showing the temporal change of the SD concentration removal rate in different PS oxidant addition amounts in the SD test in treated water using the layered oxide obtained in the sixth embodiment of example 1 of the present invention as a catalyst.

FIG. 10 is a graph showing the removal rate of SD concentration with time at different catalyst addition amounts in the experiment of treating the azo dye AO7 in water with the layered oxide obtained in the sixth embodiment of example 1 of the present invention as a catalyst.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings. Those skilled in the art will appreciate that the present invention is not limited to the drawings and the following examples.

The invention is based on the following research findings: the CuMgAl layered oxide has different microscopic compositions and structures according to different preparation methods, and further has different catalytic properties, thereby playing different catalytic roles in different application environments. At present, CuMgAl layered oxide as a catalyst for activating persulfate to obtain sulfate radical has not been studied. The inventor finds that the CuMgAl layered oxide with a microstructure in a lamellar structure can be obtained by controlling the mixing mode of a salt solution and an alkali solution and strictly controlling the pH value of a reaction system to be stable within a certain range in the reaction process when the CuMgAl layered oxide is prepared, and the product has no agglomeration phenomenon, is suitable for being used as a catalyst for activating persulfate and can be used for treating organic pollutants by a persulfate advanced oxidation technology. The CuMgAl layered oxide obtained under the preparation conditions different from those of the present invention has a microstructure in which an agglomeration phenomenon occurs and cannot be used as a catalyst for activating persulfate.