Preparation of Concentrated Stable Fluids Containing Silver Nanoparticles in Nonpolar Organic Solvent

Abstract

Stable fluids containing silver nanoparticles in kerosene have been prepared by the extraction‐reduction method. Silver nitrate was extracted in nonpolar solvent by thio‐substituted phosphinic acid extractant Cyanex 302, and then Ag⁺ was reduced by solid KBH₄. In order to enhance the loading content of silver nanoparticles in the fluids, a tri‐block copolymer (PEO)₂₀(PPO)₇₀(PEO)₂₀ was added into the organic phase before the reduction of Ag(I). The results show that Cyanex 302 acts as both an extractant for Ag⁺ from aqueous solution to kerosene and a stabilizer for silver nano particles, and the reverse micelles formed by copolymer (PEO)₂₀(PPO)₇₀(PEO)₂₀ can solubilize more silver nanoparticles modified by Cyanex 302 and prevent them from aggregating together. The highest stable concentration of silver nanoparticles in kerosene is up to 0.1 mol/L. The silver colloidal dispersions were analyzed by UV‐vis, FT‐IR spectra, TEM, and X‐ray diffraction techniques.

Keywords:

• Silver nanoparticle
• Cyanex 302
• (PEO)₂₀(PPO)₇₀(PEO)₂₀
• organic nanofluid
• nonpolar solvent

Acknowledgment

The authors thank Cytec Canada Inc. for its kindly supplying the extractant Cyanex 302.