CN112846173A - Preparation method of core-shell structure tungsten/gadolinium oxide powder for X, gamma ray protection - Google Patents

Abstract

Compared with a single metal physical blending mode, the dock/gadolinium oxide core-shell structure in the nano powder prepared by the method can play a role in cooperative protection in the aspect of radiation protection, eliminates a protection weak area and can effectively absorb secondary radiation generated by radiation. And secondly, the prepared functional powder has the characteristics of no lead and light weight, and has good application prospect in the aspect of X-ray and gamma-ray radiation protection.

Description

Preparation method of core-shell structure tungsten/gadolinium oxide powder for X, gamma ray protection

Technical Field

The invention relates to the field of preparation of radiation-proof materials, in particular to a preparation method of core-shell structure tungsten/gadolinium oxide powder for X and gamma ray protection.

Background

The development of nuclear technology brings convenience to people and simultaneously generates a lot of radiation hazards, and the light, flexible and excellent-protection-performance textile for radiation protection is a hot spot of current research. The radiation protection material is mainly divided into a lead material and a lead-free material. Lead is mainly lead, and although the protective effect is good, the lead has toxicity, poor strength and large low-energy X-ray scattering. The lead-free material mainly comprises a composite material prepared from rare earth elements and heavy metal compounds such as tin, tungsten, bismuth and the like, and has excellent protection effect, light weight and safety.

In recent years, micro-nano core-shell materials with special structures attract wide attention of people. The composite particles with different core-shell microstructures have unique physicochemical properties, so that the composite particles have wide application prospects in various fields such as optics, electronics, catalysis, biology, radiation and the like. In the aspect of radiation protection, compared with a single metal physical blending mode, the radiation protection material with the core-shell structure can realize synergistic protection, eliminate a protection weak area and effectively absorb secondary radiation generated by radiation. The preparation method of the core-shell structure mainly comprises a template method, a precipitation method, a hydrothermal synthesis method, a spray drying method, a layer-by-layer self-assembly technology and the like. Li et al prepared gadolinium oxide hollow spheres with controllable shell thickness by using silicon dioxide as a template and adopting a homogeneous precipitation method. However, these methods have disadvantages of many steps and long time, so that it is necessary to specify an effective and simple method to overcome these disadvantages. Mussel secreted adhesion protein has strong adhesion capability, which inspires that the task group of Messer Smith at the northwest university in the United states in 2007 finds that Dopamine (DA) can be oxidized and self-polymerized into polydopamine on the surface of any material under the weak base condition simulating seawater. The polymerization condition is simple and controllable, and the product has excellent adhesiveness, hydrophilicity, stability and biocompatibility. Meanwhile, a large number of phenolic hydroxyl and amino active groups exist on the polydopamine, so that abundant active sites are provided for the complexation of metal ions.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of the tungsten/gadolinium oxide powder with the core-shell structure for X and gamma ray protection.

The purpose of the invention can be realized by the following technical scheme:

the invention provides a preparation method of core-shell structure tungsten/gadolinium oxide powder for X, gamma ray protection, which comprises the following steps:

(1) preparing a dopamine salt solution, adding a buffer solution to adjust the pH value, then adding tungsten powder, stirring, filtering, washing and drying to obtain W @ PDA;

(2) adding the W @ PDA obtained in the step (1) into a gadolinium nitrate solution, stirring, filtering, and calcining at high temperature to obtain W @ Gd of a core-shell structure₂O₃And (3) powder.

According to the invention, the concentration of the prepared dopamine salt solution in the step (1) is controlled to be 1.5-2.5 g/L. Mainly because when the DA concentration is lower than 1.5g/L, only a small amount of PDA particles are deposited on the surface of W, and when the DA concentration is 1.5-2.5g/L, a PDA film is formed on the surface of W powder. When the concentration of DA is higher than 2.5g/L, larger PDA particles are formed on the surface of W powder through self-polymerization due to the fact that the concentration of DA is too high, and the subsequent adsorption of gadolinium ions is not facilitated.

It is noted that in the step (1), after the dopamine salt solution is prepared, a tris buffer solution is added into the system to adjust the pH value of the solution to 8-9, because dopamine can be polymerized into polydopamine by itself under the conditions of weak base and oxygen, and the polydopamine on the surfaces of different substances has extraordinary surface activity and adhesiveness, and can provide a platform for secondary functionalization of materials.

Further, the stirring in the step (1) needs to be carried out for 18-24 hours under an electric stirrer.

In addition, for the washing in step (1), washing with water and ethanol is required 2 to 3 times, respectively.

The specific conditions for the drying in step (1) are not particularly limited as long as the object of drying the sample can be achieved.

According to the invention, the concentration of the gadolinium nitrate solution in the step (2) should be controlled to be 0.3-0.5M/L. Because when Gd is present⁺At a concentration of 0.02M/L, the surface of W is coated with a small amount of sparse nano-dotted Gd₂O₃And (3) granules. When Gd is present⁺Gd on the W surface increased to 0.1M/L₂O₃The nanoparticles become larger and larger due to Gd⁺Increased concentration of Gd₂O₃The nanoparticles combine with each other to form larger Gd₂O₃And (3) granules. When Gd is present⁺Gd on the W surface increased to 0.2M/L₂O₃The nanoparticles become larger and more dense. With Gd⁺Gd increased in concentration to 0.3M/L, W surface₂O₃The nanoparticles are combined with each other to form W @ Gd of a core-shell structure₂O₃. Continued increase in Gd⁺Gd on the W surface at a concentration of 0.4M/L₂O₃Nanoparticles compared to Gd⁺The concentration of 0.3M/L did not change much, due to poly-dopamine on the W surface to Gd⁺Chelating agents for Gd⁺The concentration of 0.3M/L is saturated, and the waste is caused by the excessively high concentration.

Further, the stirring in the step (2) is not particularly limited, and only magnetic stirring is needed for a certain time.

In addition, the high-temperature calcination in the step (2) needs to be carried out for 2-3h under the conditions of 800-1000 ℃ in a muffle furnace, and the temperature rise is 2-4 ℃/min. In order to avoid the formation of impurities during the reaction, the calcination in step (2) of the present invention is performed in a protective gas, wherein the protective gas includes nitrogen or an inert gas, and the inert gas may be argon, helium, etc., and the present invention is not particularly limited in this respect.

As a preferred technical solution, the preparation method of the tungsten/gadolinium oxide powder with a core-shell structure for X, γ ray protection, provided by the invention, comprises the following steps:

(1) preparing 1.5g/L-2.5g/L dopamine salt solution, adding tris buffer solution to adjust the pH value to 8-9, then adding tungsten powder cleaned by ethanol, stirring for 18-24h by using an electric stirrer, filtering and separating, washing for 2-3 times by using deionized water and ethanol respectively, and drying to obtain W @ PDA:

(2) adding the W @ PDA obtained in the step (1) into gadolinium nitrate solution with the concentration of 0.3-0.5M/L, magnetically stirring for a certain time, filtering, separating, drying, introducing nitrogen into the prepared sample at the temperature of 800-₂O₃And (3) powder.

The core-shell structure W @ Gd prepared by adopting the preferred technical scheme₂O₃Compared with tungsten and gadolinium oxide blended powder, the core-shell structure can play a synergistic protection role in radiation protection, and secondary radiation generated by radiation is effectively absorbed while a protection weak area is eliminated.

Compared with the prior art, the invention at least has the following beneficial effects:

according to the invention, dopamine is firstly utilized to be self-polymerized into poly-dopamine under the condition of weak base and oxygen, and the poly-dopamine has extraordinary adhesion on the surfaces of different substances, so that tungsten can be successfully coated, and W @ PDA is obtained.

The surface of PDA contains a large amount of polar groups such as phenolic hydroxyl, amido and the like, provides rich active sites for complexing various metal ions, and can effectively react with Gd in gadolinium nitrate solution⁺Chelation was performed. After high-temperature calcination, the PDA forms a nitrogen-doped carbon layer attached to the surface of tungsten and reacts with Gd⁺Conversion of chelating W @ PDA to W @ Gd₂O₃。

Drawings

FIG. 1 is a scanning electron microscope image of the core-shell tungsten/gadolinium oxide powder prepared in example 1.

Detailed Description

To better illustrate the invention and to facilitate the understanding of the technical solutions thereof, typical but non-limiting examples of the invention are as follows:

example 1

The embodiment provides a preparation method of core-shell structure tungsten/gadolinium oxide powder for X, gamma ray protection, which comprises the following steps:

(1) preparing a dopamine salt solution with the concentration of 2g/L, adding a tris buffer solution to adjust the pH value of the solution to 8.5, then adding tungsten powder cleaned by ethanol, stirring for 24 hours by using an electric stirrer, filtering and separating, washing for 2 times by using deionized water and ethanol respectively, and drying for 5 hours at 80 ℃ to obtain W @ PDA;

(2) adding the W @ PDA obtained in the step (1) into a gadolinium nitrate solution with the concentration of 0.3M/L, magnetically stirring for 2 hours, filtering and separating, drying for 5 hours at 80 ℃, introducing nitrogen into the prepared sample at 800 ℃ and calcining at high temperature for 2 hours (the heating rate is 2 ℃/min), and finally obtaining the W @ Gd core-shell structure₂O₃And (3) powder.

W @ Gd prepared in this example₂O₃The powder was SEM-scanned, and the photograph is shown in FIG. 1, in which it was found that a PDA film was formed on the surface of the W powder.

Example 2

The embodiment provides a preparation method of core-shell structure tungsten/gadolinium oxide powder for X, gamma ray protection, which comprises the following steps:

(1) preparing 1.5g/L dopamine salt solution, adding tris buffer solution to adjust the pH value of the solution to 8, then adding tungsten powder cleaned by ethanol, stirring for 20 hours by using an electric stirrer, filtering and separating, washing for 3 times by using deionized water and ethanol respectively, and drying for 8 hours at 60 ℃ to obtain W @ PDA;

(2) adding the W @ PDA obtained in the step (1) into a gadolinium nitrate solution with the concentration of 0.35M/L, magnetically stirring for 3 hours, filtering and separating, drying for 8 hours at 60 ℃, introducing nitrogen into the prepared sample at 900 ℃ and calcining for 2.5 hours at high temperature (the heating rate is 3 ℃/min), and finally obtaining the W @ Gd of the core-shell structure₂O₃And (3) powder.

Example 3

The embodiment provides a preparation method of core-shell structure tungsten/gadolinium oxide powder for X, gamma ray protection, which comprises the following steps:

(1) preparing a dopamine salt solution with the concentration of 2.5g/L, adding a tris buffer solution to adjust the pH value of the solution to 9, then adding tungsten powder cleaned by ethanol, stirring for 18 hours by using an electric stirrer, filtering and separating, washing for 2 times by using deionized water and ethanol respectively, and drying for 6 hours at 70 ℃ to obtain W @ PDA;

(2) adding the W @ PDA obtained in the step (1) into a gadolinium nitrate solution with the concentration of 0.4M/L, magnetically stirring for 2.5h, filtering and separating, drying for 6h at 70 ℃, introducing nitrogen into the prepared sample at 1000 ℃ and calcining at high temperature for 3h (the heating rate is 4 ℃/min), and finally obtaining the W @ Gd of the core-shell structure₂O₃And (3) powder.

The embodiments described above are intended to facilitate the understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims (10)

1. A preparation method of core-shell structure tungsten/gadolinium oxide powder for X, gamma ray protection is characterized by comprising the following steps:

(1) preparing dopamine salt solution, adding buffer solution to adjust the pH value, then adding tungsten powder, stirring, filtering, washing and drying to obtain W @ PDA:

(2) adding the W @ PDA obtained in the step (1) into a gadolinium nitrate solution, stirring, filtering, and calcining at high temperature to obtain W @ Gd of a core-shell structure₂O₃And (3) powder.

2. The method for preparing the tungsten/gadolinium oxide powder with core-shell structure for X, gamma ray protection according to claim 1, wherein the buffer is added in step (1) to adjust the pH value, the buffer is tris, and the pH value is 8-9.

3. The method for preparing the tungsten/gadolinium oxide powder with the core-shell structure for protecting against X and γ rays according to claim 1, wherein the tungsten powder in the step (1) is a tungsten powder cleaned with ethanol.

4. The method for preparing the tungsten/gadolinium oxide powder with the core-shell structure for X, gamma ray protection according to claim 1, wherein the stirring in the step (1) is performed by an electric stirrer for 18-24 h.

5. The method for preparing the core-shell tungsten/gadolinium oxide powder for X, γ ray protection according to claim 1, wherein the washing in step (1) is washing with deionized water and ethanol for 2 to 3 times, respectively.

6. The method for preparing the tungsten/gadolinium oxide powder with core-shell structure for X, gamma ray protection according to claim 1, wherein the concentration of the dopamine salt solution in the step (1) is 1.5g/L to 2.5 g/L.

7. The method for preparing the tungsten/gadolinium oxide powder with core-shell structure for X, gamma ray protection as claimed in claim 1, wherein in the step (2), the high-temperature calcination temperature is 800-.

8. The method for preparing the core-shell tungsten/gadolinium oxide powder for X, γ ray protection according to claim 1, wherein the calcination in the step (2) is performed in a protective gas, and the protective gas is nitrogen or an inert gas.

9. The method for preparing the core-shell tungsten/gadolinium oxide powder for X, γ ray protection according to claim 1, wherein the concentration of the gadolinium nitrate solution in the step (2) is 0.3 to 0.5M/L.

10. A process for the preparation of the tungsten/gadolinium oxide powder with core-shell structure for X, gamma ray protection according to any of claims 1 to 9, characterized in that it comprises the following steps:

(1) preparing 1.5g/L-2.5g/L dopamine salt solution, adding tris buffer solution to adjust the pH value to 8-9, then adding tungsten powder cleaned by ethanol, stirring for 18-24h by using an electric stirrer, filtering and separating, washing for 2-3 times by using deionized water and ethanol respectively, and drying to obtain W @ PDA;

(2) adding the W @ PDA obtained in the step (1) into gadolinium nitrate solution with the concentration of 0.3-0.5M/L, magnetically stirring for a certain time, filtering, separating, drying, introducing nitrogen into the prepared sample at the temperature of 800-₂O₃And (3) powder.

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