Improved ferroferric oxide magnetic fluid and method for preparing same

A ferroferromagnetic and ferroferric oxide technology, which is applied in the fields of magnetic liquid, inductor/transformer/magnet manufacturing, electrical components, etc., can solve the problems of large particle size, limited application, impure products, etc., and achieve particle size Small diameter, wide application, and uniform particle size

Inactive Publication Date: 2010-06-30
SHANGHAI UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Nano-magnetic fluids of different sizes have been prepared, but the prepared magnetic particles have problems such as harsh reaction

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0013] Example 1: Dissolve 0.8mol / L ferric salt and 0.4mol / L ferric salt in 45mL deionized water, the ferric salt is FeCl 3 ·6H 2 O, divalent iron salt is FeSO 4 ·7H 2 O, transferred into a three-necked flask, vacuumed and filled with nitrogen, added 25%-28% (mass percentage) ammonia water to adjust the pH of the system to 9, stirred at 100°C for 1 hour, washed with ethanol and deionized water to remove excess unreacted iron ions.

[0014] The ferroferric oxide obtained by the reaction was divided into two parts, the first part was dispersed in 200mL, 3mol / L trisodium citrate solution for 1h, and washed with ethanol and deionized water until the pH was neutral to obtain the surface potential It is a magnetic fluid of -19.0mV. After the second portion was dispersed in 200 mL, 6 mol / L nitric acid solution for 1 hour, it was washed with ethanol and deionized water until the pH was neutral, and a magnetic fluid with a surface potential of +18.5 mV was obtained. The particle size of t...

Example Embodiment

[0015] Example 2: Dissolve 1.4mol / L ferric salt and 0.7mol / L ferric salt in 60mL deionized water, the ferric salt is FeCl 3 ·6H 2 O, divalent iron salt is FeSO 4 ·7H 2 O, transferred into a three-necked flask, vacuumed and filled with nitrogen, added 25%-28% (mass percentage) ammonia water to adjust the pH of the system to 9, stirred at 90°C for 1 h, washed with ethanol and deionized water to remove excess unreacted iron ions.

[0016] The ferroferric oxide obtained by the reaction was divided into two parts. The first part was dispersed in 150 mL, 2.5 mol / L trisodium citrate solution for 1.5 hours, and washed with ethanol and deionized water until the pH was neutral. A magnetic fluid with a surface potential of -15.6mV. After the second part was dispersed in 150 mL, 3.5 mol / L nitric acid solution for 1.5 hours, it was washed with ethanol and deionized water until the pH was neutral, and a magnetic fluid with a surface potential of +13.3 mV was obtained. The particle size of the ...

Example Embodiment

[0017] Example 3: Dissolve 2.6mol / L ferric salt and 1.3mol / L ferric salt in 25mL deionized water, the ferric salt is FeCl 3 ·6H 2 O, divalent iron salt is FeSO 4 ·7H 2 O, transfer into a three-necked flask, vacuum and fill with nitrogen, add 25%-28% (mass percentage) ammonia water to adjust the pH of the system to 9, 95℃, stir for 1.5h, wash with ethanol and deionized water to remove excess unreacted iron ions .

[0018] The ferroferric oxide obtained by the reaction was divided into two parts. The first part was dispersed in 300mL, 2mol / L trisodium citrate solution for 2h, and washed with ethanol and deionized water until the pH was neutral to obtain the surface potential. It is a magnetic fluid of -23.9mV. After the second portion was dispersed in 300 mL, 4 mol / L nitric acid solution for 2 hours, it was washed with ethanol and deionized water until the pH was neutral to obtain a magnetic fluid with a surface potential of +17.1 mV. The particle size of the modified magnetic flu...

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Abstract

The ferroferric oxide nano magnetic fluid prepared with the method has the particle size of 8-17 nm. The ferroferric oxide particles modified by trisodium citrate have negative electricity on the surfaces, and the Zeta potential measurement shows that the potential on the surfaces of the ferroferric oxide particles is -8.6 mV to -23.9 mV. The ferroferric oxide particles modified by nitric acid have positive electricity on the surface, and the Zeta potential measurement shows that the potential on the surfaces of the ferroferric oxide particles is +6.7 mV to +18.5 mV. Compared with the prior art, because the invention adopts lower synthesis temperature, and the nitrogen protection prevent the oxidation of divalent iron salt, the prepared magnetic particles have small and even size and electricity on surfaces, can disperse stably for a long time without agglomerating and are super paramagnetic particles which can move directionally under the condition that the magnetic field exists. The method for preparing the improved ferroferric oxide magnetic fluid comprises the following steps: adjusting the pH value of solution containing trivalent iron salt and bivalent iron salt solution to 9-10 with aqueous ammonia under the nitrogen protection, stirring the aqueous ammonia to the solution to make the aqueous ammonia react with the solution at 70-100 DEG C for 1-4h, washing the product of reaction with ethanol and deionized water repeatedly until the pH value of the product of reaction being neutral, dispersing the prepared nano magnetic ferroferric oxide in the trisodium citrate solution or the nitric acid solution, and washing the product of reaction with acetone and deionized water repeatedly to obtain the ferroferric oxide nano magnetic fluid with negative electricity or positive electricity.

Description

technical field [0001] The invention relates to two methods of modifying iron oxide nanometer magnetic fluid and its preparation method. Background technique [0002] In recent years, ferroferric oxide nanomaterials have become a hotspot in the research of magnetic nanomaterials because of their controllable size and shape and the wide application of their composites in many fields. Because of a series of unique properties such as superparamagnetism, high coercive force, low Curie temperature, and broadband strong absorption, it has been widely used in stealth absorbing materials, magnetic recording materials, and magnetic refrigeration materials. With the deepening of research and cross-infiltration between disciplines, the preparation and research of multifunctional magnetic composite microspheres that can be used in biomedicine and separation engineering related fields such as drug release and biomacromolecule separation have become a hot spot. The surface properties and...

Claims

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Application Information

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IPC IPC(8): H01F1/44H01F41/00
Inventor 颜世峰张瑛朱捷范寅清郑嬿珍尹静波
Owner SHANGHAI UNIV
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