Preparation method of nano-selenium

Abstract

The invention relates to the technical field of nano-selenium preparation, and particularly discloses a nano-selenium preparation method which mainly comprises the following steps: S1, stirring and mixing raw materials: adding ethylenediamine and ethanethiol into a beaker, then adding selenium powder into the beaker, and fully stirring and mixing at normal temperature; s2, filtering the mixture and taking filtrate: adding the filtrate stirred and mixed in S1 into a beaker, continuously stirring the filtrate at normal temperature, then adding deionized water into the beaker, continuously stirring, centrifugally separating the mixture to obtain a precipitate, and washing the precipitate with deionized water; and S3, drying: putting the precipitate obtained in S2 into a drying box, and drying to obtain the nano-selenium. Researches show that nano-selenium is prepared by taking selenium powder as a raw material, a mixture of ethanediamine and ethanethiol as a solvent and deionized water as a titration solvent through a heterogeneous titration method, and the method is safe, environment-friendly, simple and convenient to operate, low in preparation cost and easy for industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of nano-selenium preparation, in particular to a method for preparing nano-selenium. Background Art

[0002] Nanotechnology is a technology that can accurately observe, identify and control the type, quantity and structural form of matter at the level of individual atoms and molecules. It is a multidisciplinary high-tech that studies the properties and interactions of matter at the nanoscale and uses these properties to manufacture products with specific functions.

[0003] Nanomaterials have attracted extensive attention due to their unique physical and chemical properties and have been widely used in many fields. Among them, nano-selenium has been widely studied and applied in many fields in recent years due to its series of excellent properties.

[0004] As an important semiconductor material, nano-selenium is widely used in the preparation of components such as photocells, sensors and camera exposure devices because of its advantages such as anisotropy, superconductivity, and catalytic properties for hydration and oxidation reactions.

[0005] Selenium is an essential nutrient for the human body and plays an important role in human health. Nano-selenium has strong biological activity and can improve human immune function and resistance. Nano-selenium also has antioxidant and anti-cancer properties and can prevent and treat a variety of diseases. Therefore, non-toxic and highly biologically active nano-selenium is widely used in the biological and medical fields as a drug and health product.

[0006] Because selenium has a positive and important effect on the human body, highly biologically active nano-selenium can be used as an animal feed additive and a nutrient fertilizer for plants, thereby increasing the selenium content of agricultural and sideline products. People can eat selenium-rich products in their daily lives to achieve the effect of selenium supplementation. There are many types of selenium-rich products on the market, such as selenium-rich watermelon, selenium-rich flour, selenium-rich grapes, selenium-rich tea, etc., which are popular among people.

[0007] Compared with ordinary materials, nanomaterials have always been considered ideal adsorption materials because of their larger adsorption capacity, and are often used to remove heavy metals from sewage. As a type of nanomaterial, nano-selenium has the characteristics of small particle size, large specific surface area and high surface electronegativity, making it an ideal adsorption material.

[0008] At present, the preparation of selenium nanoparticles mainly adopts chemical vapor deposition method, using sodium selenate or sodium selenite as raw materials, and obtaining nano-selenium of different particle sizes through temperature control, vacuum, inert gas protection and other conditions. These preparation methods are harsh, costly and energy-intensive, which seriously limits the practical application of nano-selenium. On the other hand, selenium resources are relatively scarce, and the utilization rate is low, which causes great waste. Summary of the invention

[0009] The purpose of the present invention is to provide a method for preparing nano-selenium, which uses tin powder as a raw material, a mixture of ethylenediamine and ethanethiol as a solvent, and deionized water as a titration solvent. The nano-selenium is prepared by a heterogeneous titration method, which can not only promote the practical application and theoretical research of nano-selenium materials, but also greatly promote the development and application of elemental selenium resources.

[0010] In order to achieve the purpose of the above invention, a method for preparing nano-selenium has the following main steps:

[0011] S1. Mixing of raw materials:

[0012] First, add ethylenediamine and ethyl mercaptan into a beaker, then add selenium powder into the beaker, and stir and mix thoroughly at room temperature;

[0013] S2, filter the mixture and take the filtrate:

[0014] Add the filtrate after stirring and mixing in S1 into a beaker, continue to stir the filtrate, then add deionized water into the beaker, continue to stir, centrifuge the mixture to obtain a precipitate, and wash the precipitate with deionized water;

[0015] S3, Drying:

[0016] The precipitate obtained in S2 is placed in a drying oven for drying to obtain nano-selenium.

[0017] Specifically, in step S1, the stirring is magnetic stirring, mechanical stirring or manual stirring.

[0018] Specifically, in step S1, the volume ratio of ethylenediamine to ethanethiol is 2:1 to 13:1.

[0019] Specifically, in step S1, the mass volume ratio of the mixture of selenium powder, ethylenediamine and ethyl mercaptan is 1 / 3 to 7 / 13 g / ml.

[0020] Furthermore, the volume ratio of the deionized water to the mixture of ethylenediamine and ethanethiol is 20:1 to 500:13.

[0021] Preferably, in step S2, the deionized water is added all at once.

[0022] Specifically, in step S2, the filtrate is added to a beaker, the filtrate is vigorously stirred at 25 to 80° C., deionized water is added to the beaker at one time, stirring is continued for 3 to 10 minutes, the mixture is centrifuged at 8000 to 12000 rpm for 3 to 8 minutes to obtain a precipitate, and the precipitate is washed with deionized water 2 to 8 times.

[0023] Specifically, in step S3, the drying method is vacuum drying, forced air drying or spray drying.

[0024] Specifically, in step S3, the washed precipitate is placed in a 60° C. forced air drying oven and dried overnight to obtain nano-selenium.

[0025] The method for preparing nano-selenium of the present invention has the following advantages compared with the prior art:

[0026] A novel method for preparing nano selenium by heterogeneous titration is provided, using tin powder as a raw material, a mixture of ethylenediamine and ethyl mercaptan as a solvent, and deionized water as a titration solvent. The method comprises mixing ethylenediamine and ethyl mercaptan in a beaker, dissolving selenium powder in the mixed solution of ethylenediamine and ethyl mercaptan, filtering the mixture to obtain a filtrate, adding deionized water to the filtrate at one time, centrifuging, washing and drying to obtain nano selenium with uniform particle size, high purity and high yield. In addition, the method described in the present invention is safe, environmentally friendly, simple to operate, low in preparation cost, and easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a transmission electron microscope photograph of the nano-selenium powder prepared in Example 1 of the present invention.

[0028] Figure 2 This is the XRD pattern of the nano-selenium powder prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further explained below in conjunction with specific examples, but the examples do not limit the present invention in any form.

[0030] Example 1

[0031] First, add 6 mL of ethylenediamine and 1.5 mL of ethanethiol to a 50 mL beaker, then add 2.8 g of selenium powder to the beaker and stir the mixture at room temperature for 1 hour. Filter the mixture to obtain the filtrate, add the filtrate to a 500 mL beaker, vigorously stir the filtrate at room temperature, then add 200 mL of deionized water to the beaker at one time, continue stirring for 5 minutes, centrifuge the mixture at 10,000 rpm for 5 minutes to obtain a precipitate, and wash the precipitate with deionized water 3 times. Place the washed precipitate in a 60°C forced air drying oven and dry it overnight to obtain nano-selenium.

[0032] Example 2

[0033] First, add 6 mL of ethylenediamine and 1.5 mL of ethanethiol to a 50 mL beaker, then add 2.8 g of selenium powder to the beaker and stir the mixture at room temperature for 1 hour. Filter the mixture to obtain the filtrate, add the filtrate to a 500 mL beaker, vigorously stir the filtrate at room temperature, then add 150 mL of deionized water to the beaker at one time, continue stirring for 5 minutes, centrifuge the mixture at 10,000 rpm for 5 minutes to obtain a precipitate, and wash the precipitate with deionized water 3 times. Place the washed precipitate in a 60°C forced air drying oven and dry it overnight to obtain nano-selenium.

[0034] The difference between Example 2 and Example 1 is that the amount of deionized water added in Example 2 is 150 mL; while the amount of deionized water added in Example 1 is 200 mL.

[0035] Example 3

[0036] First, add 6 mL of ethylenediamine and 1.5 mL of ethanethiol to a 50 mL beaker, then add 2.8 g of selenium powder to the beaker and stir the mixture at room temperature for 1 hour. Filter the mixture to obtain the filtrate, add the filtrate to a 500 mL beaker, vigorously stir the filtrate at room temperature, then add 250 mL of deionized water to the beaker at one time, continue stirring for 5 minutes, centrifuge the mixture at 10,000 rpm for 5 minutes to obtain a precipitate, and wash the precipitate with deionized water 3 times. Place the washed precipitate in a 60°C forced air drying oven and dry it overnight to obtain nano-selenium.

[0037] The difference between Example 3 and Example 1 is that the amount of deionized water added in Example 3 is 250 mL; while the amount of deionized water added in Example 1 is 200 mL.

[0038] Example 4

[0039] First, add 6 mL of ethylenediamine and 1.5 mL of ethanethiol to a 50 mL beaker, then add 2.8 g of selenium powder to the beaker and stir the mixture at room temperature for 1 hour. Filter the mixture to obtain the filtrate, add the filtrate to a 500 mL beaker, vigorously stir the filtrate at room temperature, then add 200 mL of deionized water dropwise to the beaker, continue stirring for 5 minutes, centrifuge the mixture at 10,000 rpm for 5 minutes to obtain a precipitate, and wash the precipitate with deionized water 3 times. Place the washed precipitate in a 60°C forced air drying oven and dry it overnight to obtain nano-selenium.

[0040] The difference between Example 4 and Example 1 is that in Example 4, 200 mL of deionized water is added dropwise; while in Example 1, 200 mL of deionized water is added all at once.

[0041] Example 5

[0042] First, add 5 mL of ethylenediamine and 2.5 mL of ethanethiol to a 50 mL beaker, then add 2.8 g of selenium powder to the beaker and stir the mixture at room temperature for 1 hour. Filter the mixture to obtain the filtrate, add the filtrate to a 500 mL beaker, vigorously stir the filtrate at room temperature, then add 200 mL of deionized water to the beaker at one time, continue stirring for 5 minutes, centrifuge the mixture at 10,000 rpm for 5 minutes to obtain a precipitate, and wash the precipitate with deionized water 3 times. Place the washed precipitate in a 60°C forced air drying oven and dry it overnight to obtain nano-selenium.

[0043] The difference between Example 5 and Example 1 is that the volume ratio of ethylenediamine to ethyl mercaptan in Example 5 is 2 mL:1 mL; while the volume ratio of ethylenediamine to ethyl mercaptan in Example 1 is 4 mL:1 mL.

[0044] Example 6

[0045] First, add 6.5 mL of ethylenediamine and 1 mL of ethanethiol to a 50 mL beaker, then add 2.8 g of selenium powder to the beaker and stir the mixture at room temperature for 1 hour. Filter the mixture to obtain the filtrate, add the filtrate to a 500 mL beaker, vigorously stir the filtrate at room temperature, then add 200 mL of deionized water to the beaker at one time, continue stirring for 5 minutes, centrifuge the mixture at 10,000 rpm for 5 minutes to obtain a precipitate, and wash the precipitate with deionized water 3 times. Place the washed precipitate in a 60°C forced air drying oven and dry it overnight to obtain nano-selenium.

[0046] The difference between Example 6 and Example 1 is that the volume ratio of ethylenediamine to ethyl mercaptan in Example 6 is 6.5 mL:1 mL; while the volume ratio of ethylenediamine to ethyl mercaptan in Example 1 is 4 mL:1 mL.

[0047] Comparative Example 1

[0048] First, add 7.5 mL of ethylenediamine to a 50 mL beaker, then add 2.8 g of selenium powder to the beaker, and stir the mixture at room temperature for 1 hour. Filter the mixture to obtain the filtrate, add the filtrate to a 500 mL beaker, vigorously stir the filtrate at room temperature, then add 200 mL of deionized water to the beaker at one time, continue stirring for 5 minutes, centrifuge the mixture at 10,000 rpm for 5 minutes to obtain a precipitate, and wash the precipitate with deionized water 3 times. Place the washed precipitate in a 60°C forced air drying oven and dry it overnight to obtain nano-selenium.

[0049] The difference between Comparative Example 1 and Example 1 is that ethylenediamine is used as the solvent in Comparative Example 1, while a mixture of ethylenediamine and ethanethiol is used as the solvent in Example 1.

[0050] Comparative Example 2

[0051] First, add 7.5 mL of ethanethiol to a 50 mL beaker, then add 2.8 g of selenium powder to the beaker, and stir the mixture at room temperature for 1 hour. Filter the mixture to obtain the filtrate, add the filtrate to a 500 mL beaker, vigorously stir the filtrate at room temperature, then add 200 mL of deionized water to the beaker at one time, continue stirring for 5 minutes, centrifuge the mixture at 10,000 rpm for 5 minutes to obtain a precipitate, and wash the precipitate with deionized water 3 times. Place the washed precipitate in a 60°C forced air drying oven and dry it overnight to obtain nano-selenium.

[0052] The difference between Comparative Example 2 and Example 1 is that ethyl mercaptan is used as the solvent in Comparative Example 2, while a mixture of ethylenediamine and ethyl mercaptan is used as the solvent in Example 1.

[0053] Comparative Example 3

[0054] First, add 7.5 mL of ethanol to a 50 mL beaker, then add 2.8 g of selenium powder to the beaker, and stir the mixture at room temperature for 1 hour. Filter the mixture to obtain the filtrate, add the filtrate to a 500 mL beaker, vigorously stir the filtrate at room temperature, then add 200 mL of deionized water to the beaker at one time, continue stirring for 5 minutes, centrifuge the mixture at 10,000 rpm for 5 minutes to obtain a precipitate, and wash the precipitate with deionized water 3 times. Place the washed precipitate in a 60°C forced air drying oven and dry it overnight to obtain nano-selenium.

[0055] The difference between Comparative Example 3 and Example 1 is that ethanol is used as the solvent in Comparative Example 3, while a mixture of ethylenediamine and ethanethiol is used as the solvent in Example 1.

[0056] The particle sizes and yields of the nano-selenium prepared in Examples 1 to 6 and Comparative Examples 1 to 3 are shown in Table 1.

[0057] Table 1

[0058]

[0059] It can be seen from the experimental data in Table 1 that the average particle size of the nano-selenium prepared by Example 1 is 30 nm and the yield is 2.79 g. This shows that the nano-selenium prepared by the heterogeneous titration method using tin powder as raw material, a mixture of ethylenediamine and ethanethiol as solvent, and deionized water as titration solvent has a small average particle size and a high yield.

[0060] The average particle size and yield of the nano-selenium prepared in Example 1 and Example 2-3 were studied and analyzed to find that the amount of deionized water added had an important influence on the average particle size and yield of the nano-selenium. The average particle size of the nano-selenium in Example 2-3 was larger than that of the nano-selenium in Example 1, and the yield of the nano-selenium in Example 2-3 was smaller than that of the nano-selenium in Example 1. This shows that in the process of preparing nano-selenium using the method described in the present invention, the selection of the amount of deionized water added plays an important role in the average particle size and yield of the prepared nano-selenium. When the amount of deionized water added was 200 mL, the average particle size of the prepared nano-selenium was small and the yield was high. The main reason is that when the amount of deionized water added was less than 200 mL, the nano-selenium synthesis was insufficient due to the insufficient amount of deionized water added. When the amount of deionized water added was higher than 200 mL, the nano-selenium nucleation was too late due to the excessive addition of deionized water, and the nano-selenium synthesis was also insufficient.

[0061] The average particle size and yield of the nano-selenium prepared in Example 1 and Example 4 were found to be significantly affected by the method of adding 200 mL of deionized water. The average particle size of the nano-selenium in Example 4 was larger than that in Example 1, and the yield of the nano-selenium in Example 4 was less than that in Example 1. This shows that in the process of preparing nano-selenium using the method described in the present invention, the selection of the method of adding 200 mL of deionized water plays an important role in the average particle size and yield of the prepared nano-selenium. When the method of adding 200 mL of deionized water is selected to be added at one time, the average particle size of the prepared nano-selenium is small and the yield is high, mainly because the nano-selenium can be rapidly nucleated when the deionized water is added at one time, and the nano-selenium can be quickly synthesized. If the method of adding 200 mL of deionized water is selected to be added dropwise, the nano-selenium nucleation speed is too slow and the nano-selenium synthesis is insufficient due to the slow addition speed of deionized water.

[0062] The average particle size and yield of the nano-selenium prepared in Example 1 and Example 5-6 are studied and analyzed to find that the volume ratio of ethylenediamine and ethyl mercaptan in Example 1 has an important influence on the average particle size and yield of the nano-selenium. The average particle size of the nano-selenium in Example 5-6 is larger than that in Example 1, and the yield of the nano-selenium in Example 5-6 is smaller than that in Example 1. This shows that in the process of preparing nano-selenium by the method described in the present invention, the selection of the volume ratio of ethylenediamine and ethyl mercaptan in Example 1 plays an important role in the average particle size and yield of the prepared nano-selenium. When the volume ratio of ethylenediamine and ethyl mercaptan in Example 1 is selected as 4mL:1mL, the average particle size of the prepared nano-selenium is small and the yield is high. The main reason is that when the volume ratio of ethylenediamine and ethyl mercaptan is lower or higher than 4mL:1mL, the tin powder will not be fully dissolved, which will lead to too low selenium concentration in the filtrate and insufficient nucleation during the synthesis of nano-selenium.

[0063] The study of Example 1 and Comparative Examples 1 to 3 found that the nano-selenium prepared by using a mixture of ethylenediamine and ethyl mercaptan as a solvent has a small average particle size and a high yield. Comparative Examples 1 to 2 respectively use ethylenediamine and ethyl mercaptan alone to prepare nano-selenium, indicating that the solvent must use a mixture of ethylenediamine and ethyl mercaptan to prepare nano-selenium with a small average particle size and a high yield. In addition, Comparative Example 3 uses ethanol as a solvent and also fails to prepare nano-selenium, indicating that other types of solvents are not suitable for preparing nano-selenium.

Claims

1. A method for preparing nano-selenium, characterized in that: The main steps are as follows: S1. Mixing of raw materials: First, add ethylenediamine and ethyl mercaptan into a beaker, then add selenium powder into the beaker, and stir and mix thoroughly at room temperature; S2, filter the mixture and take the filtrate: Add the filtrate after stirring and mixing in S1 into a beaker, continue to stir the filtrate, then add deionized water into the beaker, continue to stir, centrifuge the mixture to obtain a precipitate, and wash the precipitate with deionized water; S3, Drying: The precipitate obtained in S2 is placed in a drying oven for drying to obtain nano-selenium.

2. The method for preparing nano-selenium according to claim 1, characterized in that: In step S1, the stirring is magnetic stirring, mechanical stirring or manual stirring.

3. The method for preparing nano-selenium according to claim 1, characterized in that: In step S1, the volume ratio of ethylenediamine to ethanethiol is 2:1 to 13:

1.

4. The method for preparing nano-selenium according to claim 3, characterized in that: In step S1, the mass volume ratio of the mixture of selenium powder, ethylenediamine and ethyl mercaptan is 1 / 3 to 7 / 13 g / ml.

5. The method for preparing nano-selenium according to claim 4, characterized in that: In step S2, the volume ratio of the deionized water to the mixture of ethylenediamine and ethanethiol is 20:1 to 500:

13.

6. The method for preparing nano-selenium according to claim 5, characterized in that: In step S2, the deionized water is added all at once.

7. The method for preparing nano-selenium according to claim 6, characterized in that: In step S2, the filtrate is added to a beaker, the filtrate is vigorously stirred at 25-80° C., deionized water is added to the beaker at once, stirring is continued for 3-10 minutes, the mixture is centrifuged at 8000-12000 rpm for 3-8 minutes to obtain a precipitate, and the precipitate is washed 2-8 times with deionized water.

8. The method for preparing nano-selenium according to any one of claims 1 to 7, characterized in that: In step S3, the drying method is vacuum drying, forced air drying or spray drying.

9. The method for preparing nano-selenium according to claim 8, characterized in that: In step S3, the washed precipitate is placed in a 60° C. forced air drying oven and dried overnight to obtain nano-selenium.

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