Method for preparing nanosilver powder in batches

A technology of nano-silver powder and mass production, which is applied in the direction of nano-technology, can solve the problems of nano-silver agglomeration, agglomeration, and uneven particle size of nano-silver, and achieve the effect of increased surface area, uniform distribution of crystal seeds, and controllable quantity

Active Publication Date: 2015-09-23

NANO TOP ELECTRONICS TECH

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AI-Extracted Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is to provide a new method for synthesizing, separating and preparing nano-silver powder in batches. The particle size of the nano-silver powder prepared by the present invention i...

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Abstract

The invention provides a method for preparing nanosilver powder in batches, belonging to the field of nano-material preparation. Nanosilver particles are synthetized in two steps, at first, a low-concentration reducing agent solution is slowly added into a solution mixed with silver salt, a protective agent, and a pH conditioning agent drop by drop, and then a high-concentration reducing agent solution is rapidly added drop by drop to obtain a nanosilver mixed solution; impurities in the nanosilver mixed solution are removed through a membrane separation device to obtain a nanosilver dispersion liquid; and at the end, absolute ethyl alcohol and a high-molecular dispersant are added into the nanosilver dispersion liquid, and spray drying is carried out by a spray drying device to obtain nanosilver powder in a certain particle size. The particle size of the prepared nanosilver powder is controllable, the batches are stable, the problems of non-uniform particle size during the synthesis of nanosilver, nanosilver separation, and agglomeration and acaking during powder preparation are solved, the preparation process and the operation are simple, and industrial and batches production is realized.

Application Domain

Nanotechnology

Technology Topic

Batch productionHigh concentration +7

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Examples

Experimental program(3)

Example Embodiment

[0036] Example 1:

[0037] The preparation flow chart of nano silver powder is attached figure 1 :

[0038] (1) Weigh 150g of dimethylaminomethacrylamide/acrylic acid copolymer and dissolve it in 40L of dewatered water, then add 1020g of silver nitrate to dissolve, adjust pH=9 with 4% mass fraction of dilute ammonia water, and use a metering pump to add to the above solution Slowly add 8L dropwise to 5×10 -3 mol/L ascorbic acid aqueous solution, the dripping rate is 0.2mL/min; then, use a metering pump to quickly add 15L of 0.2mol/L ascorbic acid aqueous solution to the above solution, the dripping rate is 10mL/min, and continue to stir for 0.5h after dripping. Obtaining a nano silver mixed solution;

[0039] (2) Pass the nano-silver mixed solution obtained in step (1) through a membrane separation device (see attached figure 2 ) Perform membrane separation, the ultrafiltration membrane material is polyacrylonitrile, and the membrane pore size is 30nm. Pour the mixed solution into the material tank, then add deionized water, open the circulation pump and pipeline valve, the nano-silver reaction solution is automatically and selectively separated through the membrane module, and after three cycles, the impurity content of thermogravimetric analysis is 0.1wt% , And finally concentrate the material liquid in the material tank to 20L for discharging to obtain nano silver dispersion;

[0040] (3) Add 5% volume fraction of absolute ethanol and 0.2% volume fraction of polyethylene glycol 200 to the nano silver dispersion obtained in step (2) for spray drying. The drying equipment is a pressure spray dryer and the circulating air volume is 85%, the inlet air temperature is 140°C.

[0041] The average particle size of the nano silver powder prepared in this embodiment is 50 nm. The ultraviolet-visible absorption spectrum of the nano silver powder is shown in the attachment image 3.

Example Embodiment

[0042] Example 2:

[0043] The preparation flow chart of nano silver powder is attached figure 1 :

[0044] (1) Weigh 150g of polyacrylic acid (PAA) and dissolve in 50L of deionized water, then add 340g of silver nitrate and stir to dissolve, use a micropipette to slowly inject 80mL into the above solution with a concentration of 8×10 -3 mol/L maltose aqueous solution, the dripping rate is 0.05mL/min; then, quickly inject 8.75L maltose aqueous solution with a concentration of 0.12mol/L with a micropipette, the dripping rate is 60mL/min, and continue to stir for 1h to obtain nano silver mixture;

[0045] (2) Pass the nano-silver mixed solution obtained in step (1) through a membrane separation device (see attached figure 2 ) Perform membrane separation, the ultrafiltration membrane material is polystyrene, and the membrane pore size is 50 nm. Pour the mixed solution into the material tank, then add deionized water, open the circulating pump and pipeline valve, the nano-silver mixed solution is automatically selectively separated through the membrane module, after 5 cycles, the impurity content of thermogravimetric analysis is 0.12wt% , Finally, the material liquid in the material tank is concentrated 3 times and discharged to obtain a nano-silver dispersion liquid;

[0046] (3) Add 3% volume fraction of absolute ethanol and 0.5% volume fraction of dispersant PEG400 to the nano-silver dispersion obtained in step (2) for spray drying. The drying equipment is a high-speed centrifugal spray dryer with a rotation speed of 42000r/ min, the inlet air temperature is 135℃.

[0047] The average particle size of the nano silver powder prepared in this embodiment is 100 nm. The ultraviolet-visible absorption spectrum of the nano silver powder is shown in the attachment Figure 4.

Example Embodiment

[0048] Example 3:

[0049] The preparation flow chart of nano silver powder is attached figure 1 :

[0050] (1) Weigh 300g of polyvinyl alcohol and dissolve in 20L of deionized water, then add 340g of silver sulfate and stir to dissolve, use a metering pump to slowly drop 0.5L into the solution to a concentration of 1×10 -3 mol/L sodium hypophosphite aqueous solution, the dropping rate is 0.4mL/min; then, quickly drop 4.17L of 0.12mol/L sodium hypophosphite aqueous solution with a metering pump, the dropping rate is 20mL/min, and continue to stir for 1.5h , To obtain a nano-silver mixed solution;

[0051] (2) Pass the nano-silver mixed solution obtained in step (1) through a membrane separation device (see attached figure 2 ) To carry out membrane separation, the ultrafiltration membrane material is polyvinyl chloride, the pore size of the ultrafiltration membrane is 40nm; pour the mixture into the material tank, then add deionized water, turn on the circulation pump and pipeline valve, the nano silver mixed solution passes through the membrane The components are automatically separated selectively. After 6 cycles, the impurity content of thermogravimetric analysis is 0.1wt%. Finally, the material liquid in the tank is concentrated 4 times and discharged to obtain the nano-silver dispersion liquid;

[0052] (3) Add 6% volume fraction of absolute ethanol and 0.1% volume fraction of dispersant PVP K30 to the nano silver dispersion obtained in step (2) for spray drying. The drying equipment is an airflow spray dryer and the nozzle is a two-fluid Nozzle, compressed air pressure 0.6MPa.

[0053] The average particle size of the nano silver powder prepared in this embodiment is 60 nm, and the ultraviolet-visible absorption spectrum of the nano silver powder is shown in the attachment Figure 5.

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PUM

Property	Measurement	Unit
Aperture	1.0 ~ 100.0	nm
Particle size	1.0 ~ 500.0	nm
Membrane pore size	30.0	nm
tensile		MPa
Particle size		Pa
strength	10

Description & Claims & Application Information

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ActiveCN102040670ASimple methodLow equipment requirementsCosmetic preparationsToilet preparationsChemistryMethyl group

Owner:FROG PRINCE (FUJIAN) BABY & CHILD CARE PROD CO LTD

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Method for preparing nanosilver powder in batches

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Image

Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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