A method for preparing spherical silver nanopowder induced by epoxide and the silver nanopowder

Abstract

The present invention relates to the technical field of nanomaterial preparation, and discloses a method for preparing spherical silver nanometer powder induced by epoxide and the silver nanometer powder, which comprises the following steps: preparing a silver source solution, dropping an epoxide into the silver source solution under stirring conditions to obtain a mixed solution, preparing a reducing agent solution, mixing the reducing agent solution with the mixed solution, stirring at room temperature for 30 min, with a stirring speed of 200-600 rpm, then performing a heat reaction treatment to obtain a reaction product, and centrifuging, washing and drying the reaction product to obtain spherical silver nanometer powder; in the preparation process of the application, no dispersion protective agent is added, an epoxide is used as an inducer, and a saccharide substance is used as a reducing agent, and spherical silver nanometer powder with uniform particle size and morphology is prepared by controlling the concentration of reaction substances, the reaction temperature and the reaction time.

Description

Technical Field

[0001] The present invention relates to the technical field of nanomaterial preparation, and particularly relates to a method for preparing spherical silver nanometer powder induced by epoxide and the silver nanometer powder. Background Art

[0002] As an important industrial raw material, silver nanometer powder is widely used in many fields such as electronic materials, photosensitive materials, catalysts, medicines, and antibacterial materials due to the surface effect, quantum size effect, etc. unique to nanomaterials. Among many preparation technical routes, the liquid-phase reduction process is simple and the equipment cost is relatively low, which is the most widely used method for large-scale industrial production at present. However, there are still some technical problems in the preparation process of silver nanomaterial, such as complex reaction components, cumbersome preparation process, adding strong base or weak base to control the pH value of the reaction system, and even special equipment is required. These have limited the practical application of the synthesis method of silver nanomaterial to a certain extent, and are more unfavorable for the large-scale production of this material;

[0003] Chinese Patent Application No. 202010845718.6 discloses a spherical silver nanometer powder, its preparation method and application. By adding a regulator to adjust the pH to 10-13, and then adding a dispersant and a reducing agent to prepare spherical silver nanometer powder. The spherical silver powder prepared by this method has a wide size distribution, low sphericity, poor particle size stability, and the preparation process is cumbersome and the raw material cost is relatively high. Therefore, how to improve the particle size and morphology uniformity of silver nanometer powder has always been a research hotspot. Summary of the Invention

[0004] The main purpose of the present invention is to provide a method for preparing spherical silver nanometer powder induced by epoxide and the silver nanometer powder to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing spherical silver nanometer powder induced by epoxide, comprising the following steps:

[0007] S1, dissolving a silver source in solvent A to obtain a silver source solution, and the concentration of the silver source solution is 0.5-2 mol / L;

[0008] S2, dropping an epoxide into the silver source solution under stirring conditions to obtain a mixed solution;

[0009] S3, dissolving a reducing agent in solvent B to obtain a reducing agent solution, and the concentration of the reducing agent solution is 0.5-3 mol / L;

[0010] S4. After mixing the reducing agent solution with the mixed solution obtained in Step S2, pour the mixture into a reaction kettle, stir it at room temperature for 30 min at a stirring speed of 200 - 600 rpm, and perform a heating reaction treatment on the reaction kettle to obtain a reaction product;

[0011] S5. The reaction product obtained in Step S4 is centrifuged to obtain a precipitate, which is then washed with ultrapure water and anhydrous ethanol and dried to obtain spherical silver nanoparticles;

[0012] The epoxide in Step S2 is one or more of ethylene oxide, propylene oxide, 1,4 - epoxybutane, and epichlorohydrin.

[0013] Further, the silver source is one or more of silver nitrate, silver carbonate, silver oleate, and silver chloride.

[0014] Further, the molar ratio of the epoxide to the silver source is (1 - 6):1.

[0015] Further, the dropping rate in Step S2 is 500 - 800 ml / min.

[0016] Further, the reducing agent is one or more of glucose, D - glucal, fructose, D - cellobiose, xylose, maltose, ribose, sucrose, and lactose.

[0017] Further, the solvent A or solvent B is one or more of methanol, ethanol, isopropanol, ethylene glycol, butanediol, and N,N - dimethylformamide.

[0018] Further, the molar ratio of the silver source to the reducing agent is 1:(1 - 3).

[0019] Further, the reaction temperature in Step S4 is 80 - 120 °C, and the reaction time is 1 - 12 h.

[0020] Further, the centrifugation conditions in Step S5 are a rotation speed of 5000 rpm and a centrifugation time of 3 min. The washing conditions are to wash 2 - 3 times with ultrapure water and then 2 - 3 times with anhydrous ethanol. The drying method is one of vacuum drying, air - blast drying, or rake drying, the drying temperature is 50 - 60 °C, and the drying time is 8 h.

[0021] The present invention also provides silver nanoparticles prepared by the method for preparing spherical silver nanoparticles induced by the foregoing epoxide. The particle size of the silver nanoparticles is 60 - 1200 nm.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] In the method of the present application, no dispersing and protecting agent is added during the preparation process. Dispersants are usually some organic or inorganic compounds. Even after subsequent purification steps such as washing and separation during the preparation of nano-silver powder, it is very difficult to completely remove the dispersant residues. These residual dispersants will become impurities in the nano-silver powder, affecting the purity and performance of the nano-silver powder;

[0024] 2. In the method of the present application, by using an epoxide as an inducer and a saccharide as a reducing agent, spherical nano-silver powder with uniform particle size and morphology is prepared by controlling the concentration, reaction temperature and reaction time of the reaction substances. The epoxide has a certain solubility in the silver source and the saccharide, can make the reaction system more uniform, can be miscible with common solvents, is conducive to the uniform dispersion of silver ions and the smooth progress of the reduction reaction of the saccharide to silver ions, thus helping to obtain nano-silver powder with a narrow particle size distribution and regular morphology;

[0025] 3. The preparation process of the present application is simple, the raw material cost is low, and it is easy to carry out large-scale industrial production. Description of the Drawings

[0026] Figure 1 It is the SEM image of the nano-silver powder prepared in Example 1 of the present invention;

[0027] Figure 2 It is the SEM image of the nano-silver powder prepared in Example 2 of the present invention;

[0028] Figure 3 It is the SEM image of the nano-silver powder prepared in Example 3 of the present invention;

[0029] Figure 4 It is the SEM image of the nano-silver powder prepared in Example 4 of the present invention. Detailed Embodiments

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. Example 1

[0031] S1. Prepare a silver source solution: Weigh 17.0 g of analytical pure silver nitrate and add it to 200 ml of ethylene glycol. After stirring and dissolving for 10 min, a silver source solution with a concentration of 0.5 mol / L is obtained;

[0032] S2. Under stirring conditions, 17.4 g of propylene oxide was added dropwise to the silver source solution at a rate of 500 ml / min through a peristaltic pump. After stirring and dissolving for 15 min, a mixed solution was obtained.

[0033] S3. Prepare a reducing agent solution: Dissolve 45.0 g of xylose in 200 ml of ethylene glycol. After stirring for 10 min, a reducing agent solution with a concentration of 1.5 mol / L was obtained.

[0034] S4. After mixing the reducing agent solution with the mixed solution obtained in step S2, pour it into a reaction kettle, stir at room temperature for 30 min with a stirring speed of 300 rpm, heat the reaction kettle to 100 °C and react for 8 h to obtain a reaction product.

[0035] S5. The reaction product obtained in step S4 was centrifuged at a centrifugal speed of 5000 rpm for 3 min to obtain a precipitate. The precipitate was washed 3 times each with ultrapure water and absolute ethanol, and then placed in a blast drying oven and dried at 50 °C for 8 h to obtain spherical silver nanoparticles. Example 2

[0036] S1. Prepare a silver source solution: Weigh 17.0 g of analytical pure silver nitrate and add it to 200 ml of ethylene glycol. After stirring and dissolving for 10 min, a silver source solution with a concentration of 0.5 mol / L was obtained.

[0037] S2. Under stirring conditions, 17.4 g of propylene oxide was added dropwise to the silver source solution at a rate of 600 ml / min through a peristaltic pump. After stirring and dissolving for 15 min, a mixed solution was obtained.

[0038] S3. Prepare a reducing agent solution: Dissolve 45.0 g of xylose in 200 ml of ethylene glycol. After stirring for 10 min, a reducing agent solution with a concentration of 1.5 mol / L was obtained.

[0039] S4. After mixing the reducing agent solution with the mixed solution obtained in step S2, pour it into a reaction kettle, stir at room temperature for 30 min with a stirring speed of 300 rpm, heat the reaction kettle to 120 °C and react for 8 h to obtain a reaction product.

[0040] S5. The reaction product obtained in step S4 was centrifuged at a centrifugal speed of 5000 rpm for 3 min to obtain a precipitate. The precipitate was washed 3 times each with ultrapure water and absolute ethanol, and then placed in a blast drying oven and dried at 50 °C for 8 h to obtain spherical silver nanoparticles. Example 3

[0041] S1, Prepare the silver source solution: Weigh 17.0 g of analytical pure silver nitrate and add it to 200 ml of ethylene glycol. After stirring and dissolving for 10 min, a silver source solution with a concentration of 0.5 mol / L is obtained;

[0042] S2, Under stirring conditions, add 17.4 g of propylene oxide dropwise to the silver source solution at a rate of 700 ml / min through a peristaltic pump. After stirring and dissolving for 15 min, a mixed solution is obtained;

[0043] S3, Prepare the reducing agent solution: Dissolve 45.0 g of xylose in 200 ml of ethylene glycol. After stirring for 10 min, a reducing agent solution with a concentration of 1.5 mol / L is obtained;

[0044] S4, Mix the reducing agent solution with the mixed solution obtained in step S2, pour it into a reaction kettle, stir at room temperature for 30 min with a stirring speed of 300 rpm, heat the reaction kettle to 100 °C and react for 4 h to obtain a reaction product;

[0045] S5, Centrifuge the reaction product obtained in step S4 at a centrifugal speed of 5000 rpm for 3 min to obtain a precipitate. Wash the precipitate 3 times each with ultrapure water and absolute ethanol, and place it in a blast drying oven to dry at 50 °C for 8 h to obtain spherical silver nanoparticles. Example 4

[0046] S1, Prepare the silver source solution: Weigh 17.0 g of analytical pure silver nitrate and add it to 200 ml of ethylene glycol. After stirring and dissolving for 10 min, a silver source solution with a concentration of 0.5 mol / L is obtained;

[0047] S2, Under stirring conditions, add 29.0 g of propylene oxide dropwise to the silver source solution at a rate of 800 ml / min through a peristaltic pump. After stirring and dissolving for 15 min, a mixed solution is obtained;

[0048] S3, Prepare the reducing agent solution: Dissolve 45.0 g of xylose in 200 ml of ethylene glycol. After stirring for 10 min, a reducing agent solution with a concentration of 1.5 mol / L is obtained;

[0049] S4, Mix the reducing agent solution with the mixed solution obtained in step S2, pour it into a reaction kettle, stir at room temperature for 30 min with a stirring speed of 300 rpm, heat the reaction kettle to 100 °C and react for 8 h to obtain a reaction product;

[0050] S5, Centrifuge the reaction product obtained in step S4 at a centrifugal speed of 5000 rpm for 3 min to obtain a precipitate. Wash the precipitate 3 times each with ultrapure water and absolute ethanol, and place it in a blast drying oven to dry at 50 °C for 8 h to obtain spherical silver nanoparticles. Example 5

[0051] S1. Prepare a silver source solution: Weigh 34.0 g of analytical pure silver nitrate and add it to 200 ml of ethylene glycol. After stirring and dissolving for 10 min, a silver source solution with a concentration of 1.0 mol / L is obtained;

[0052] S2. Under stirring conditions, add 69.6 g of propylene oxide dropwise to the silver source solution at a rate of 500 ml / min through a peristaltic pump. After stirring and dissolving for 15 min, a mixed solution is obtained;

[0053] S3. Prepare a reducing agent solution: Dissolve 15.0 g of xylose in 200 ml of ethylene glycol. After stirring for 10 min, a reducing agent solution with a concentration of 0.5 mol / L is obtained;

[0054] S4. Mix the reducing agent solution with the mixed solution obtained in step S2, pour it into a reaction kettle, stir at room temperature for 30 min with a stirring speed of 200 rpm, heat the reaction kettle to 80 °C and react for 12 h to obtain a reaction product;

[0055] S5. Centrifuge the reaction product obtained in step S4 at a centrifuge speed of 5000 rpm for 3 min to obtain a precipitate. Wash the precipitate with ultrapure water and absolute ethanol twice each, and place it in a blast drying oven to dry at 60 °C for 8 h to obtain spherical silver nanoparticles; Example 6

[0056] S1. Prepare a silver source solution: Weigh 68.0 g of analytical pure silver nitrate and add it to 200 ml of ethylene glycol. After stirring and dissolving for 10 min, a silver source solution with a concentration of 2.0 mol / L is obtained;

[0057] S2. Under stirring conditions, add 23.2 g of propylene oxide dropwise to the silver source solution at a rate of 800 ml / min through a peristaltic pump. After stirring and dissolving for 15 min, a mixed solution is obtained;

[0058] S3. Prepare a reducing agent solution: Dissolve 90.0 g of xylose in 200 ml of ethylene glycol. After stirring for 10 min, a reducing agent solution with a concentration of 3.0 mol / L is obtained;

[0059] S4. Mix the reducing agent solution with the mixed solution obtained in step S2, pour it into a reaction kettle, stir at room temperature for 30 min with a stirring speed of 600 rpm, heat the reaction kettle to 120 °C and react for 1 h to obtain a reaction product;

[0060] The reaction product obtained in step S4 and S5 is centrifuged at a rotational speed of 5000 rpm for 3 minutes to obtain a precipitate. The precipitate is first washed 3 times with ultrapure water and then washed 2 times with absolute ethanol, and then placed in a blast drying oven and dried at 60 °C for 8 hours to obtain spherical silver nanopowder.

[0061] Comparative Example 1

[0062] The preparation method of Comparative Example 1 of the present invention is the same as that of Example 1 in other aspects, except that no epoxide is added during the preparation.

[0063] Comparative Example 2

[0064] The preparation method of Comparative Example 1 of the present invention is the same as that of Example 1 in other aspects, except that 58.0 g of propylene oxide is added during the preparation.

[0065] Comparative Example 3

[0066] The preparation method of Comparative Example 1 of the present invention is the same as that of Example 1 in other aspects, except that the dropping rate of the peristaltic pump during the preparation is 100 ml / min.

[0067] Comparative Example 4

[0068] The preparation method of Comparative Example 1 of the present invention is the same as that of Example 1 in other aspects, except that the dropping rate of the peristaltic pump during the preparation is 2000 ml / min.

[0069] The particle morphology, particle size distribution range and product dispersibility of the products of Examples 1-6 and Comparative Examples 1-4 are detected. The detection results are shown in Table 1. Among them, the particle morphology and dispersibility of the products are measured by SEM electron microscopy scanning, and the particle size distribution is measured by a laser particle size analyzer.

[0070] Table 1

[0071]

[0072] In the preferred specific embodiments of the present invention, it should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should fall within the protection scope determined by the claims.

Claims

1. A method for preparing spherical nano silver powder under epoxide induction, characterized in that: The steps include: S1, dissolving a silver source in solvent A to obtain a silver source solution, wherein the concentration of the silver source solution is 0.5 mol / L; S2, under stirring, adding the epoxide dropwise to the silver source solution to obtain a mixed solution; S3, dissolving the reducing agent in solvent B to obtain a reducing agent solution, wherein the concentration of the reducing agent solution is 0.5-3 mol / L; S4, mixing the reducing agent solution with the mixed solution obtained in step S2, pouring the mixture into a reactor, stirring at room temperature for 30 minutes at a stirring speed of 200-600 rpm, and heating the reactor for reaction to obtain a reaction product; S5, the reaction product obtained in step S4 is centrifuged to obtain a precipitate, which is then washed with ultrapure water and anhydrous ethanol and then dried to obtain spherical nano silver powder; The epoxide in step S2 is one or more of ethylene oxide, propylene oxide, 1,4-butylene oxide and epichlorohydrin; The method does not add a dispersion protection agent.

2. The method for preparing spherical nano silver powder under epoxide induction according to claim 1, characterized in that: The silver source is one or more of silver nitrate, silver carbonate, silver oleate and silver chloride.

3. The method for preparing spherical nano silver powder under epoxide induction according to claim 1, characterized in that: The molar ratio of the epoxide to the silver source is (1-6):

1.

4. The method for preparing spherical nano silver powder under epoxide induction according to claim 1, characterized in that: The droplet acceleration rate in the step S2 is 500-800 ml / min.

5. The method for preparing spherical nano silver powder under epoxide induction according to claim 1, characterized in that: The reducing agent is one or more of glucose, D-glucal, fructose, D-cellobiose, xylose, maltose, ribose, sucrose and lactose.

6. The method for preparing spherical nano silver powder under epoxide induction according to claim 1, characterized in that: The solvent A or solvent B is one or more of methanol, ethanol, ethylene glycol, butanediol, and N,N-dimethylamide.

7. The method for preparing spherical nano silver powder under epoxide induction according to claim 1, characterized in that: The molar ratio of the silver source to the reducing agent is 1:

1.

8. The method for preparing spherical nano silver powder under epoxide induction according to claim 1, characterized in that: In the step S4, the reaction temperature is 80-100° C. and the reaction time is 1-4 h.

9. The method for preparing spherical nano silver powder under epoxide induction according to claim 1, characterized in that: In the step S5, the centrifugal condition is a rotation speed of 5000 rpm, the centrifugal time is 3 minutes, the washing condition is to use ultrapure water to wash 2-3 times, and then wash with anhydrous ethanol 2-3 times, the drying method is one of vacuum drying, blast drying or rake drying, the drying temperature is 60° C., and the drying time is 8 hours.

10. A nano silver powder, prepared by the method for preparing spherical nano silver powder under the induction of epoxide according to any one of claims 1 to 9.

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