Promising polymer-assisted extraction of palladium from supported catalysts in supercritical carbon dioxide

Andrea Ruiu (1) , Bernhard Bauer-Siebenlist (2) , Marin Senila (3) , Thorsten Jänisch (4) , Dominique Foix (5) , Karine Seaudeau-Pirouley (6) , Patrick Lacroix-Desmazes (1)

1 ICGM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier
2 Heraeus Deutschland GmbH & Co. KG
3 Research Institute for Analytical Instrumentation
4 Fraunhofer ICT - Fraunhofer Institute for Chemical Technology
5 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux
6 IFS - Innovation Fluides Supercritiques

Precious metals, in particular palladium (Pd), have a wide range of daily applications, from automotive catalysts to fine chemistry production. Nevertheless, these metals are relatively rare and highly expensive, considering their massive industrial utilization. In the last decades, different recycling methods have been explored. Nowadays, the most applied methods, namely pyro- and/or hydrometallurgy, involve energy-intensive processes and/or the generation of large amounts of effluents to be treated. Thus, the development of a more sustainable recycling process of precious metals is highly desirable. In the present work, we introduce a sustainable process based on the use of a green solvent, supercritical CO2, operated under mild conditions (P = 25 MPa and T = 40 °C). The extraction process is possible thanks to the addition of CO2-soluble complexing polymers bearing pyridine units. The proposed method leads to the extraction of more than 70 % of Pd from an aluminosilica-supported catalyst.

Keywords: Catalyst; Extraction; Palladium; Polymer; Supercritical fluid

Domains: Material chemistry; Polymers

Andrea Ruiu, Bernhard Bauer-Siebenlist, Marin Senila, Thorsten Jänisch, Dominique Foix, et al.. Promising polymer-assisted extraction of palladium from supported catalysts in supercritical carbon dioxide. Journal of CO2 Utilization, 2020, 41, pp.101232. ⟨10.1016/j.jcou.2020.101232⟩. ⟨hal-02927491⟩