2014-Sustainable Industrial Processing Summit
SIPS 2014 Volume 6: Rare Earths & Ionic Liquids
| Editors: | Kongoli F |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2014 |
| Pages: | 432 pages |
| ISBN: | 978-1-987820-08-9 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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High efficient recovery of Pt from spent PEM fuel cells by hydrometallurgy : Platinium concentration in solution by ion exchange resin
Emmanuel Billy1; Richard Laucournet1; Denis Vincent1;1CEA, Grenoble, France;
Type of Paper: Regular
Id Paper: 41
Topic: 9
Abstract:
Nowadays, energy efficiency and renewable energies are central concerns to develop sustainable energy. Among the diversity of technologies, Proton Exchange Membrane Fuel Cells (PEMFCs) represent a promising alternative to cater for energy requirements in the next decades. PEM fuel cells release electrical energy through two electrochemical reactions performed on platinum nanoparticles supported on carbon and separated by a polymer membrane.
Currently, the commercial membrane electrode assemblies (MEAs) contain a Pt-loading between 4 mg.cm-2 and 0.15 mg.cm-2. This loading represents 0.5 % to 2.0 %wt of catalytic element in the MEAs. It is widely accepted that the high cost and limited supply of platinum are considered as issues to large scale commercialization of PEMFCs. To overcome these hurdles, the strategies aim at reducing the Pt-loading for minimizing the system cost and recovering the platinum to secure the platinum supply. The conventional approach to recover platinum from MEAs includes a pyro/hydrometallurgical process combusting the PEM and the carbonaceous diffusion layers, dissolving the resultant ash in aqua regia and purifying the precious metal using standard refining.
In this study, we put forward a hydrometallurgical approach to recover 80% platinum from MEAs by a separation of the membrane and catalyst layers, lixiviation and recovery by precipitation. The residual platinum in solution (2g/l) was treated by ion exchange resins (IERs). A large study has been dedicated to define the most suitable resin among three different resins. The IERs have been studied in unequilibrium and equilibrium conditions of sorption. The prediction of the rate-limiting step and kinetic parameters were investigated. Moreover, the Langmuir, Freundlich, and Temkin-Pyzhev isotherm models were applied. These data are critical for defining the best conditions for sorption and design appropriate sorption treatment plant.
Finally, desorption has been studied regarding: nature, concentration, pH and ionic strength of the solution.