This paper concerns the oxidative dissolution ability of a thioamide/iodine leaching system in water towards gold, palladium and silver metals in powder in view of a potential application in the recovery process of these metals from electrical and electronic waste equipment (E-waste). The leaching mixture composed of equimolar amounts of thioamide 3-methyl-benzothiazole-2-thione and I2 in water can oxidize/complex gold and palladium metals in powder in order to form the complexes [AuI(mbtt)2]I3 and [PdII(mbtt)3I]I3. Considering the mild conditions under which the processes were performed ([I2] = 1.14 × 10-3 M, T = 20 °C, pH = 5.0, leaching time = 24 h), the obtained oxidation yield of Au0 and Pd0 are to be considered satisfactory with values of 65% and 69%, respectively. No oxidation was observed for the silver powder. The oxidising/complexing properties of the leaching mixture mbtt + I2 were interpreted considering the formation of the mbtt-I2 adduct that features, as a consequence of the S-donor to I2 interaction, a charge separation between the bridging and terminal iodine atoms in the fragment S-Ib-It. The feasibility of recovering gold from the complex [AuI(mbtt)2]I3 was verified by performing a cementation with magnesium powder.
Gold and palladium oxidation/complexation in water by a thioamide-iodine leaching system / F. Isaia, M.C. Aragoni, M. Arca, C. Caltagirone, C. Castellano, G. De Filippo, A. Garau, V. Lippolis, T. Pivetta. - In: GREEN CHEMISTRY. - ISSN 1463-9262. - 19:19(2017), pp. 4591-4599.
|Titolo:||Gold and palladium oxidation/complexation in water by a thioamide-iodine leaching system|
|Parole Chiave:||Printed-circuit boards; Copper(I) halide-complexes; N-methylbenzothiazole-2-thione synthesis; antibacterial activity; molecular adducts; secondary sources; precious metals; basis-sets; recovery; hydrometallurgy|
|Settore Scientifico Disciplinare:||Settore CHIM/03 - Chimica Generale e Inorganica|
|Data di pubblicazione:||2017|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1039/c7gc01310h|
|Appare nelle tipologie:||01 - Articolo su periodico|