0434418 - GLÚ 2015 RIV NL eng J - Journal Article
Šebek, O. - Mihaljevič, M. - Strnad, L. - Ettler, V. - Ježek, J. - Štědrý, R. - Drahota, P. - Ackerman, Lukáš - Adamec, V.
Dissolution kinetics of Pd and Pt from automobile catalysts by naturally occurring complexing agents.
Journal of Hazardous Materials. Roč. 198, December (2011), s. 331-339. ISSN 0304-3894. E-ISSN 1873-3336
Institutional research plan: CEZ:AV0Z30130516
Keywords : automobile catalyst * Platinum group elements * mobilisation * leaching * kinetic
Subject RIV: DD - Geochemistry
Impact factor: 4.173, year: 2011

Powder samples prepared from gasoline (Pt, Pd, Rh, new GN/old GO) and diesel (Pt, new DN/old DO) catalysts and recycled catalyst NIST 2556 were tested using kinetic leaching experiments following 1, 12, 24, 48, 168, 360, 720 and 1440-h interactions with solutions of 20 mM citric acid (CA), 20 mM Na₂P₄O₇ (NaPyr), 1 g L⁻¹ NaCl (NaCl), a fulvic acid solution (FA–DOC 50 mg L⁻¹) and 20 mM CA at pH 3, 4, 5, 6, 7, 8 and 9. The mobilisation of platinum group elements (PGEs) was fastest in solutions of CA and NaPyr. In the other interactions (NaCl, FA), the release of PGEs was probably followed by immobilisation processes, and the interactions were not found to correspond to the simple release of PGEs into solution. Because of their low concentrations, the individual complexing agents did not have any effect on the speciation of Pd and Pt in the extracts; both metals are present in solution as the complexes Me(OH)₂, Me(OH)⁺. Immobilisation can take place through the adsorption of the positively charged hydroxyl complexes or flocculation of fulvic acid, complexing the PGEs on the surface of the extracted catalysts. The calculated normalised bulk released NRi values are similar to the reaction rate highest in the solutions of CA and NaPyr.
Permanent Link: http://hdl.handle.net/11104/0238478