Method for preparing spherical nano silver powder under epoxide induction and nano silver powder

Abstract

The invention relates to the technical field of nano-material preparation, and discloses a method for preparing spherical nano-silver powder under epoxide induction and nano-silver powder, and the method comprises the following steps: preparing a silver source solution, dropwise adding epoxide into the silver source solution under the stirring condition to obtain a mixed solution, preparing a reducing agent solution, and preparing the spherical nano-silver powder under the induction of epoxide. The reducing agent solution and the mixed solution are mixed and then stirred for 30 min at the room temperature, the stirring rotating speed is 200-600 rpm, then heating reaction treatment is conducted, a reaction product is obtained, and spherical nano silver powder is obtained after the reaction product is centrifuged, washed and dried; in the preparation process, a dispersion protective agent is not added, the epoxide is used as an inducer, the carbohydrates are used as a reducing agent, and the spherical nano silver powder uniform in particle size and morphology is prepared by controlling the concentration, the reaction temperature and the reaction time of the reaction substances.

Description

Technical Field

[0001] The invention relates to the technical field of nano material preparation, and in particular to a method for preparing spherical nano silver powder under epoxide induction and the nano silver powder. Background Art

[0002] As an important industrial raw material, nanosilver powder is widely used in many fields such as electronic materials, photosensitive materials, catalysts, medicines and antibacterial materials due to its surface effects and quantum size effects that are unique to nanomaterials. Among the many preparation technology routes, the liquid phase reduction process is simple and has low equipment costs. It is currently the most widely used method for large-scale production in the industry. However, there are still some technical difficulties in the preparation of nanosilver materials, such as complex reaction components, cumbersome preparation processes, adding strong or weak bases to control the pH value of the reaction system, and even requiring special equipment. These have limited the practical application of the synthesis method of nanosilver materials to a certain extent, and are not conducive to the large-scale production of the material. Chinese patent application No. 202010845718.6 discloses a spherical nano silver powder and its preparation method and application, wherein the pH is adjusted to 10-13 by adding a regulator, and a dispersant and a reducing agent are added thereto to prepare the spherical nano silver powder. The spherical silver powder prepared by this method has a wide size distribution, low sphericity, poor particle size stability, and a cumbersome preparation process, and the raw material cost is relatively high. Therefore, how to improve the particle size and morphology uniformity of nano silver powder has always been a hot topic of research. Summary of the invention

[0003] The main purpose of the present invention is to provide a method for preparing spherical nano silver powder under epoxide induction and nano silver powder, so as to solve the problems raised in the above background technology.

[0004] To achieve the above object, the technical solution adopted by the present invention is: A method for preparing spherical nano silver powder under epoxide induction comprises the following steps: S1, dissolving a silver source in solvent A to obtain a silver source solution, wherein the concentration of the silver source solution is 0.5-2 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.

[0005] Furthermore, the silver source is one or more of silver nitrate, silver carbonate, silver oleate and silver chloride.

[0006] Furthermore, the molar ratio of the epoxide to the silver source is (1-6):1.

[0007] Furthermore, the dripping rate in step S2 is 500-800 ml / min.

[0008] Furthermore, the reducing agent is one or more of glucose, D-glucal, fructose, D-cellobiose, xylose, maltose, ribose, sucrose, and lactose.

[0009] Furthermore, the solvent A or solvent B is one or more of methanol, ethanol, isopropanol, ethylene glycol, butanediol, and N,N-dimethylamide.

[0010] Furthermore, the molar ratio of the silver source to the reducing agent is 1:(1-3).

[0011] Furthermore, in the step S4, the reaction temperature is 80-120° C., and the reaction time is 1-12 h.

[0012] Furthermore, in the S5 step, the centrifugation condition is a rotation speed of 5000 rpm, the centrifugation time is 3 minutes, the washing condition is washing with ultrapure water 2-3 times, and then washing with anhydrous ethanol 2-3 times, the drying method is one of vacuum drying, blast drying or rake drying, the drying temperature is 50-60°C, and the drying time is 8 hours.

[0013] The present invention also provides nano silver powder prepared by the method for preparing spherical nano silver powder under the induction of epoxide, wherein the particle size of the nano silver powder is 60-1200nm.

[0014] Compared with the prior art, the present invention has the following beneficial effects: In the method of the present application, no dispersing protective agent is added during the preparation process. The dispersing agent is usually some organic or inorganic compounds. Even after the subsequent purification steps such as washing and separation, it is difficult to completely remove the dispersing agent residues when the dispersing agent is used in the preparation process of the nano silver powder. These residual dispersing agents will become impurities in the nano silver powder, affecting the purity and performance of the nano silver powder. 2. The method of the present application uses epoxide as an inducing agent and a sugar substance as a reducing agent, and controls the concentration of the reactants, the reaction temperature and the reaction time to prepare spherical nano silver powder with uniform particle size and morphology. The epoxide can have a certain solubility for the silver source and the sugar substance, can make the reaction system more uniform, can be well miscible with common solvents, is conducive to the uniform dispersion of silver ions and the smooth reduction reaction of the sugar substance on the silver ions, thereby helping to obtain nano silver powder with a narrow particle size distribution and a more regular morphology; 3. The preparation process of the present invention is simple, the cost of raw materials is low, and it is easy for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a SEM image of the nano silver powder prepared in Example 1 of the present invention; Figure 2 This is a SEM image of the nano silver powder prepared in Example 2 of the present invention; Figure 3 This is a SEM image of the nano silver powder prepared in Example 3 of the present invention; Figure 4 This is a SEM image of the nano silver powder prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Example 1

[0017] S1, preparing a silver source solution: weighing 17.0 g of analytical pure silver nitrate, adding it to 200 ml of ethylene glycol, stirring and dissolving for 10 min to obtain a silver source solution with a concentration of 0.5 mol / L; 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 by a peristaltic pump, and the mixture was stirred and dissolved for 15 min to obtain a mixed solution; S3, preparing a reducing agent solution: dissolving 45.0 g of xylose in 200 ml of ethylene glycol, stirring for 10 min, to obtain a reducing agent solution with a concentration of 1.5 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 min, with a stirring speed of 300 rpm, heating the reactor to 100° C. and reacting for 8 h to obtain a reaction product; S5, the reaction product obtained in step S4 is centrifuged at a centrifugal speed of 5000 rpm for 3 min to obtain a precipitate, which is washed three times with ultrapure water and three times with anhydrous ethanol, and then placed in a forced air oven and dried at 50° C. for 8 h to obtain spherical nano silver powder. Example 2

[0018] S1, preparing a silver source solution: weighing 17.0 g of analytical pure silver nitrate, adding it to 200 ml of ethylene glycol, stirring and dissolving for 10 min to obtain a silver source solution with a concentration of 0.5 mol / L; 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 by a peristaltic pump, and the mixture was stirred and dissolved for 15 min to obtain a mixed solution; S3, preparing a reducing agent solution: dissolving 45.0 g of xylose in 200 ml of ethylene glycol, stirring for 10 min, to obtain a reducing agent solution with a concentration of 1.5 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 min, with a stirring speed of 300 rpm, heating the reactor to 120° C. and reacting for 8 h to obtain a reaction product; S5, the reaction product obtained in step S4 is centrifuged at a centrifugal speed of 5000 rpm for 3 min to obtain a precipitate, which is washed three times with ultrapure water and three times with anhydrous ethanol, and then placed in a forced air oven and dried at 50° C. for 8 h to obtain spherical nano silver powder. Example 3

[0019] S1, preparing a silver source solution: weighing 17.0 g of analytical pure silver nitrate, adding it to 200 ml of ethylene glycol, stirring and dissolving for 10 min to obtain a silver source solution with a concentration of 0.5 mol / L; S2, under stirring conditions, 17.4 g of propylene oxide was added dropwise to the silver source solution at a rate of 700 ml / min by a peristaltic pump, and the mixture was stirred and dissolved for 15 min to obtain a mixed solution; S3, preparing a reducing agent solution: dissolving 45.0 g of xylose in 200 ml of ethylene glycol, stirring for 10 min, to obtain a reducing agent solution with a concentration of 1.5 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 min, with a stirring speed of 300 rpm, heating the reactor to 100° C. and reacting for 4 h to obtain a reaction product; S5, the reaction product obtained in step S4 is centrifuged at a centrifugal speed of 5000 rpm for 3 min to obtain a precipitate, which is washed three times with ultrapure water and three times with anhydrous ethanol, and then placed in a forced air oven and dried at 50° C. for 8 h to obtain spherical nano silver powder. Example 4

[0020] S1, preparing a silver source solution: weighing 17.0 g of analytical pure silver nitrate, adding it to 200 ml of ethylene glycol, stirring and dissolving for 10 min to obtain a silver source solution with a concentration of 0.5 mol / L; S2, under stirring conditions, 29.0 g of propylene oxide was added dropwise to the silver source solution at a rate of 800 ml / min by a peristaltic pump, and the mixture was stirred and dissolved for 15 min to obtain a mixed solution; S3, preparing a reducing agent solution: dissolving 45.0 g of xylose in 200 ml of ethylene glycol, stirring for 10 min, to obtain a reducing agent solution with a concentration of 1.5 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 min, with a stirring speed of 300 rpm, heating the reactor to 100° C. and reacting for 8 h to obtain a reaction product; S5, the reaction product obtained in step S4 is centrifuged at a centrifugal speed of 5000 rpm for 3 min to obtain a precipitate, which is washed three times with ultrapure water and three times with anhydrous ethanol, and then placed in a forced air oven and dried at 50° C. for 8 h to obtain spherical nano silver powder. Example 5

[0021] S1, preparing a silver source solution: weighing 34.0 g of analytical pure silver nitrate, adding it to 200 ml of ethylene glycol, stirring and dissolving for 10 min to obtain a silver source solution with a concentration of 1.0 mol / L; S2, under stirring, adding 69.6 g of propylene oxide to the silver source solution at a rate of 500 ml / min by a peristaltic pump, stirring and dissolving for 15 min to obtain a mixed solution; S3, preparing a reducing agent solution: dissolving 15.0 g of xylose in 200 ml of ethylene glycol, stirring for 10 min, to obtain a reducing agent solution with a concentration of 0.5 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 min, with a stirring speed of 200 rpm, heating the reactor to 80° C. and reacting for 12 h to obtain a reaction product; S5, the reaction product obtained in step S4 is centrifuged at a centrifugal speed of 5000 rpm for 3 min to obtain a precipitate, which is washed twice with ultrapure water and twice with anhydrous ethanol, and then placed in a forced air oven and dried at 60° C. for 8 h to obtain spherical nano silver powder. Example 6

[0022] S1, preparing a silver source solution: weighing 68.0 g of analytical pure silver nitrate, adding it to 200 ml of ethylene glycol, stirring and dissolving for 10 min to obtain a silver source solution with a concentration of 2.0 mol / L; S2, under stirring conditions, 23.2 g of propylene oxide was added dropwise to the silver source solution at a rate of 800 ml / min by a peristaltic pump, and the mixture was stirred and dissolved for 15 min to obtain a mixed solution; S3, preparing a reducing agent solution: dissolving 90.0 g of xylose in 200 ml of ethylene glycol, stirring for 10 min, to obtain a reducing agent solution with a concentration of 3.0 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, the stirring speed is 600 rpm, heating the reactor to 120° C. and reacting for 1 hour to obtain a reaction product; S5, the reaction product obtained in step S4 is centrifuged at a centrifugal speed of 5000 rpm for 3 min to obtain a precipitate, which is first washed 3 times with ultrapure water and then washed twice with anhydrous ethanol, and then placed in a blast oven and dried at 60° C. for 8 h to obtain spherical nano silver powder.

[0023] Comparative Example 1 The preparation method of Comparative Example 1 of the present invention is otherwise the same as that of Example 1, except that no epoxide is added during the preparation.

[0024] Comparative Example 2 The preparation method of Comparative Example 1 of the present invention is otherwise the same as that of Example 1, except that 58.0 g of propylene oxide is added during the preparation.

[0025] Comparative Example 3 The rest of the preparation method of Comparative Example 1 of the present invention is the same as that of Example 1, except that the dripping rate of the peristaltic pump is 100 ml / min during the preparation.

[0026] Comparative Example 4 The rest of the preparation method of Comparative Example 1 of the present invention is the same as that of Example 1, except that the dripping rate of the peristaltic pump is 2000 ml / min during the preparation.

[0027] The particle morphology, particle size distribution range and product dispersibility of the products of Examples 1-6 and Comparative Examples 1-4 were tested, and the test results are shown in Table 1, wherein the particle morphology and dispersibility of the products were measured by SEM electron microscope scanning, and the particle size distribution was measured by a laser particle size analyzer.

[0028] Table 1

[0029] It should be understood that the preferred specific embodiments of the present invention can be modified and varied by ordinary technicians in the field without creative work. Therefore, any technical solution that can be obtained by technicians in the field of technology through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection 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 0.5-2 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.

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, isopropanol, 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:(1-3).

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 80-120° C. and the reaction time is 1-12 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 50-60° 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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