The uptake characteristics of Prussian-blue nanoparticles for rare metal ions for recycling of precious metals from nuclear and electronic wastes
Shinta Watanabe, Yusuke Inaba, Miki Harigai, Kenji Takeshita, Jun Onoe
Abstract
Abstract We have examined the uptake mechanisms of platinum-group-metals (PGMs) and molybdenum (Mo) ions into Prussian blue nanoparticles (PBNPs) in a nitric acid solution for 24-h sorption test, using inductively coupled plasma atomic emission spectroscopy, powder XRD, and UV–Vis-NIR spectroscopy in combination with first-principles calculations, and revealed that the Ru 4+ and Pd 2+ ions are incorporated into PBNPs by substitution with Fe 3+ and Fe 2+ ions of the PB framework, respectively, whereas the Rh 3+ ion is incorporated into PBNPs by substitution mainly with Fe 3+ and minorly with Fe 2+ ion, and Mo 6+ ion is incorporated into PBNPs by substitution with both Fe 2+ and Fe 3+ ions, with maintaining the crystal structure before and after the sorption test. Assuming that the amount of Fe elusion is equal to that of PGMs/Mo substitution, the substitution efficiency is estimated to be 39.0% for Ru, 47.8% for Rh, 87% for Pd, and 17.1% for Mo 6+ . This implies that 0.13 g of Ru, 0.16 g of Rh, 0.30 g of Pd, and 0.107 g of Mo can be recovered by using 1 g PBNPs with a chemical form of KFe(III)[Fe(II)(CN) 6 ].