Ultrasonic irradiation and solvent effects on destabilization of colloidal suspensions of platinum nanoparticles

In this work, ultrasonic irradiation and destabilizer solvent were used for destabilizing colloidal platinum dispersions. The stabilized platinum nanoparticles were prepared in w/o microemulsion systems composed of sodium bis-(2-ethylhexyl) sulfosuccinate (AOT) and four different solvents, namely, cyclohexane, n-hexane, n-heptane, and n-nonane. The recovery process of Pt nanoparticles from the colloidal systems was performed by exposing the colloidal samples to ultrasonic irradiation and applying various destabilizing solvents. Analysis of UV–visible spectra confirms that the quantity of Pt nanoparticles removed from the suspension depends on the length of time of the ultrasonic irradiation and the nature of the microemulsion oil phase. A critical time for the ultrasonic irradiation has been introduced for the phase separation of colloidal systems. To perform the solvent study, four destabilizer solvents, namely, dioxane, ethyl acetate, diethyl ether, and tetrahydrofuran, were used for breaking the colloidal suspension of platinum nanoparticles. Based on the ‘good solvent’ and ‘poor solvent’ idea, it is verified that the effect of the destabilizer solvents on the aggregation process follows the following order: tetrahydrofuran > ethyl acetate > dioxane > diethyl ether.