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Title Recovery of Precious Metals: A Promising Process Using Supercritical Carbon Dioxide and CO2-Soluble Complexing Polymers for Palladium Extraction from Supported Catalysts
ID_Doc 21807
Authors Ruiu, A; Li, WSJ; Senila, M; Bouilhac, C; Foix, D; Bauer-Siebenlist, B; Seaudeau-Pirouley, K; Jänisch, T; Böringer, S; Lacroix-Desmazes, P
Title Recovery of Precious Metals: A Promising Process Using Supercritical Carbon Dioxide and CO2-Soluble Complexing Polymers for Palladium Extraction from Supported Catalysts
Year 2023
Published Molecules, 28.0, 17
DOI 10.3390/molecules28176342
Abstract Precious metals such as palladium (Pd) have many applications, ranging from automotive catalysts to fine chemistry. Platinum group metals are, thus, in massive demand for industrial applications, even though they are relatively rare and belong to the list of critical materials for many countries. The result is an explosion of their price. The recovery of Pd from spent catalysts and, more generally, the development of a circular economy process around Pd, becomes essential for both economic and environmental reasons. To this aim, we propose a sustainable process based on the use of supercritical CO2 (i.e., a green solvent) operated in mild conditions of pressure and temperature (p = 25 MPa, T = 313 K). Note that the range of CO2 pressures commonly used for extraction is going from 15 to 100 MPa, while temperatures typically vary from 308 to 423 K. A pressure of 25 MPa and a temperature of 313 K can, therefore, be viewed as mild conditions. CO2-soluble copolymers bearing complexing groups, such as pyridine, triphenylphosphine, or acetylacetate, were added to the supercritical fluid to extract the Pd from the catalyst. Two supported catalysts were tested: a pristine aluminosilicate-supported catalyst (Cat D) and a spent alumina supported-catalyst (Cat A). An extraction conversion of up to more than 70% was achieved in the presence of the pyridine-containing copolymer. The recovery of the Pd from the polymer was possible after extraction, and the technological and economical assessment of the process was considered.
Author Keywords catalyst extraction; supercritical CO2; palladium recycling; fluoropolymers; complexing polymers; sustainable chemistry; circular economy
Index Keywords Index Keywords
Document Type Other
Open Access Open Access
Source Science Citation Index Expanded (SCI-EXPANDED)
EID WOS:001064167900001
WoS Category Biochemistry & Molecular Biology; Chemistry, Multidisciplinary
Research Area Biochemistry & Molecular Biology; Chemistry
PDF https://www.mdpi.com/1420-3049/28/17/6342/pdf?version=1693450670
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