Issue 19, 2017

Gold and palladium oxidation/complexation in water by a thioamide–iodine leaching system

Abstract

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.

Graphical abstract: Gold and palladium oxidation/complexation in water by a thioamide–iodine leaching system

Supplementary files

Article information

Article type
Paper
Submitted
02 May 2017
Accepted
11 Aug 2017
First published
15 Aug 2017

Green Chem., 2017,19, 4591-4599

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 and T. Pivetta, Green Chem., 2017, 19, 4591 DOI: 10.1039/C7GC01310H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements