2018 Volume 82 Issue 12 Pages 461-466
A novel method to produce palladium micrometer-sized particles is presented. This method consists of the leaching of palladium using dimethyl sulfoxide (DMSO) solution containing CuCl2 and NaCl followed by the precipitation with citric acid aqueous solution. Precisely, palladium was dissolved in a DMSO solution containing 0.1-0.2 M of CuCl2 and 0-0.2 M of NaCl at 343 K. The dissolved palladium was precipitated by the addition of a citric acid aqueous solution, and the dried precipitates were imaged using standard SEM. We obtained micrometer-sized particles: angular particles were formed by the addition of 0.1-0.5 M citric acid aqueous solution while spherical particles by 1.0-2.0 M citric acid solution. The maximum recovery efficiency of palladium was 76.1% and purity of palladium was 92.5 mass%. To investigate the mechanism of particle formation, in-situ monitoring of the formations of palladium particles in the liquid phase was conducted using atmospheric scanning electron microscopy (ASEM). The monitoring revealed that palladium particles form coral-like branching strings in the liquid phase. Comparison with dried spherical particles suggests that the stings were changed into spherical shapes during drying.
