Method for preparing nano silver particles

A technology of nano-silver particles and silver nitrate, which is applied in the field of preparation of nano-silver particles, can solve the problems of high cost, low production efficiency of physical methods, and high energy consumption, and achieve the effects of small particle size, mild reaction conditions, and simple separation steps

Active Publication Date: 2010-11-03
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Physical methods mainly include gas phase evaporation and condensation method, grinding method and atomization method, etc., but physical method has low production efficiency, high cost and high energy consumption; chemical method includes reduction protection method, microemulsion method, phase transfer method, etc. Simple, high yield and other advantages

Method used

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  • Method for preparing nano silver particles
  • Method for preparing nano silver particles

Examples

Experimental program
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Effect test

Embodiment 1

[0016] 60g of silver nitrate is dissolved in 500mL of water, and 60mL of 25% concentrated ammonia water is added thereto to form a silver-ammonia complex solution, 15g of lauric acid is added to the solution, and 120mL of concentrated ammonia is added under stirring to adjust its pH value to promote Dissolution of lauric acid. After the lauric acid is completely dissolved, increase the stirring speed to 800rpm, add dropwise 400mL aqueous solution containing 4g of sodium borohydride, the whole dropping process lasts for 30min, continue to stir and react for 20min after the dropping is completed, and the whole reaction process is maintained at room temperature . Thereafter, the stirring speed was reduced to 100 rpm, and 200 mL of 20% (V / V) phosphoric acid was slowly added thereto. After the addition, it was allowed to stand and filtered to obtain a black solid. The obtained black solid was washed successively with 250 mL of methanol and 250 mL of ethanol, and filtered again to...

Embodiment 2

[0018] 100g of silver nitrate was dissolved in 1000mL of water, and 125mL of 40% methylamine aqueous solution was added thereto to form a silver-ammonia complex solution, and 16g of sodium n-octoate was added to the solution, and stirred to completely dissolve the sodium n-octoate. Thereafter, the stirring speed was increased to 500 rpm, and 48 g of 37% formaldehyde aqueous solution was added dropwise thereto. The whole dropping process lasted for 30 minutes, and the stirring reaction was continued for 60 minutes after the dropping was completed. Reduce the stirring speed to 200 rpm, and slowly inject 150 mL of 25% (V / V) phosphoric acid into the system. After the addition, it was allowed to stand and filtered to obtain a black solid. The obtained black solid was washed successively with 250 mL of ethanol and 250 mL of acetone, and filtered again to obtain "wet" silver nanoparticles, which were dried in a vacuum to obtain about 45 g of silver nanoparticles.

Embodiment 3

[0020] Dissolve 60g of silver nitrate in 1200mL of water, add 90g of ethylenediaminetetraacetic acid disodium salt (EDTA) to it to form a silver complex solution, add 15g of lauric acid to the above solution, and add 100g of 10% NaOH aqueous solution under stirring Adjust its pH to facilitate the dissolution of lauric acid. After the lauric acid is completely dissolved, increase the stirring speed to 1200rpm, and dropwise add 20mL of 40% hydrazine hydrate dropwise. The whole dropping process lasts for 30 minutes. After the dropping is completed, continue stirring for 20 minutes. room temperature. Thereafter, the stirring speed was reduced to 150 rpm, and 250 mL of 15% (V / V) phosphoric acid was slowly added thereto. After the addition, it was allowed to stand and filtered to obtain a black solid. The obtained black solid was washed twice with 500 mL of ethanol (250 mL each time), and filtered again to obtain "wet" silver nano-particles. After vacuum drying, about 27 g of silv...

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Abstract

The invention provides a method for preparing and separating nano silver particles. The method comprises the following steps of: preparing mixed aqueous solution of AgNO3 and a complexing agent of AgNO3 first, adding a certain amount of surfactant, adjusting the pH value of the system then, stirring the system to completely dissolve the added surfactant, adding a reducer into the solution dropwise with vigorous stirring, controlling the reaction temperature to be room temperature and continuously stirring the mixed solution after the reducer is completely dropped to obtain nano solver sol till the end of the reaction; and adjusting the pH value of the nano solver sol to be subacid or neutral (pH=2-7) by adopting a pH value regulator, allowing solids to be dissolved, separating the solids, washing the solids with an organic solvent, separating the mixed liquid again to obtain 'wet' nano silver particles and drying the 'wet' nano silver particles under vacuum to obtain the nano silver particles. The nano silver particles prepared by the method are small in particle size (less than 50 nanometers), the preparation process has mild reaction conditions (room temperature), and the subsequent separation steps are simple (centrifugal separation is not required).

Description

technical field [0001] The invention belongs to the field of preparation of nanometer materials, and in particular relates to a preparation method of nanometer silver particles. Background technique [0002] Due to the small size effect, surface effect and quantum size effect, nano metal particles show different thermal, optical, electrical, magnetic and catalytic properties from bulk materials, so they are used in optoelectronics, catalysis, chemical sensors, magnetic materials, Life medicine and other fields have potential application prospects. [0003] Silver is the metal with the best conductivity among all metals (conductivity is 6.62×10 5 S cm -1 ), is the cheapest precious metal, and has good chemical inertness. Therefore, both bulk metallic silver and silver particles of various shapes (flaky, spherical, etc.) and sizes (micron, submicron, nanometer, etc.) have been widely used. [0004] The preparation methods of nano-silver particles can be roughly divided int...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/24
Inventor 刘建国曾晓雁王小叶李祥友
Owner HUAZHONG UNIV OF SCI & TECH
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