Electrophoretic Concentration of Nanoparticles of Gold in Reversed Micellar Solutions of AOT

The electrophoretic mobility of nanoparticles of gold in reversed micelles of AOT was determined, and the nanoparticle electrokinetic potential was calculated. The electrokinetic potential of the particles decreased from 43 to 17 mV with the fall in the solubilization capacity from 1 to 0.2 vol. %. Correspondingly, the hydrodynamic radius decreased from 2.9 to 1.8 nm. On the basis of the electrokinetic studies, a new concentration method was developed, allowing concentration of metal particles with an enrichment factor of similar to 10(3). A simple model of the concentration has been proposed as a process of electrophoretic separation of micelles with gold nanoparticles from the empty ones. The limiting gold concentration in the liquid cathode concentrate (similar to 1 mol/L) and the concentrate volume have been calculated depending on the organic-phase volume, the solubilization capacity of the micellar solution, and the initial metal ion concentration.