Dissolution behavior of precious metals and selective palladium leaching from spent automotive catalysts by trihalide ionic liquids
The dissolution behavior of the precious metals gold, platinum, rhodium and palladium in the trihexyl(tetradecyl)phosphonium trihalide ionic liquids [P 66614 ][Cl 3 ], [P 66614 ][Br 3 ], [P 66614 ][IBr 2 ] and [P 66614 ][I 3 ] was investigated. The highest dissolution rates were observed for the tri...
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Published in | RSC advances Vol. 11; no. 17; pp. 111 - 112 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
England
Royal Society of Chemistry
09.03.2021
The Royal Society of Chemistry |
Subjects | |
Online Access | Get full text |
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Summary: | The dissolution behavior of the precious metals gold, platinum, rhodium and palladium in the trihexyl(tetradecyl)phosphonium trihalide ionic liquids [P
66614
][Cl
3
], [P
66614
][Br
3
], [P
66614
][IBr
2
] and [P
66614
][I
3
] was investigated. The highest dissolution rates were observed for the trichloride ionic liquid [P
66614
][Cl
3
] and this system was investigated in more detail. The effects of the trichloride concentration in the ionic liquid and temperature were studied, reaching higher leaching rates at higher trichloride conversions and increased temperatures. The stability of the trichloride anion at these elevated temperatures was studied by Raman spectroscopy. It was found that the trichloride anion decomposed during leaching at higher temperatures, showing the requirement to store these reactive compounds in sealed and cool environments, shielded from light. The optimal leaching conditions were applied for the recovery of palladium from ceramic monolith powder, obtained from end-of-life automotive catalysts. The catalyst powder was contacted with the ionic liquid [P
66614
][Cl
3
] and the metal concentrations in the ionic liquid were monitored. The trihalide ionic liquid allowed a more selective leaching of palladium compared to other metals present at very high concentrations in the monolith structure, like magnesium. The relative ratio of palladium over magnesium increased by two orders of magnitude compared to the original catalyst composition. The effect of the contact time between the catalyst powder and the ionic liquid on the metal concentrations in the leachate was investigated, but no significant improvement in the selectivity was observed.
Trichloride ionic liquids were used to increase the leaching selectivity of palladium from spent automotive catalyst with a ceramic support. |
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Bibliography: | Electronic supplementary information (ESI) available: Mass losses, ICP-OES data and limit of detection determination of palladium and rhodium wires. See DOI 10.1039/d1ra00695a ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2046-2069 2046-2069 |
DOI: | 10.1039/d1ra00695a |