TY - JOUR
T1 - Palladium release from catalytic converter materials induced by road de-icer components chloride and ferrocyanide
AU - Aruguete, Deborah M.
AU - Wallace, Adam
AU - Blakney, Terry
AU - Kerr, Rose
AU - Gerber, Galen
AU - Ferko, Jacob
N1 - Funding Information:
D.M.A. acknowledges Penn State Behrend startup funds for supporting this research, as well as the Lake Erie Research Institute and the Hirtzel Memorial Fund who sponsored the purchase and support of the ICPMS used for this work. She thanks Mr. Jerome Magraw, senior technician at Penn State Behrend, for innumerable conversations regarding ICP-MS measurements. R.K. acknowledges support from a Penn State Behrend Summer Research Fellowship Grant (2017). Finally, the authors thank the anonymous reviewers for providing commentary that very much improved this work. The abovementioned sources of funding played no role in this study, nor did they play any role in the writing or submitting of this article.
Funding Information:
D.M.A. acknowledges Penn State Behrend startup funds for supporting this research, as well as the Lake Erie Research Institute and the Hirtzel Memorial Fund who sponsored the purchase and support of the ICPMS used for this work. She thanks Mr. Jerome Magraw, senior technician at Penn State Behrend, for innumerable conversations regarding ICP-MS measurements. R.K. acknowledges support from a Penn State Behrend Summer Research Fellowship Grant ( 2017 ). Finally, the authors thank the anonymous reviewers for providing commentary that very much improved this work. The abovementioned sources of funding played no role in this study, nor did they play any role in the writing or submitting of this article. Appendix A
Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2020/4
Y1 - 2020/4
N2 - Environmental levels of platinum group elements (PGEs) are rising due to emissions of vehicle catalytic converter (VCC) materials containing palladium, platinum and rhodium. When these PGE-containing VCC materials are exposed to soil and water, coordination complex formation with ligands present in the environment may mobilize PGEs into solution, particularly Pd. Road de-icing salt contains two ligands with high affinities for Pd2+: chloride (Cl−) from NaCl and cyanide (CN−) from ferrocyanide (Fe(CN)64−) anti-caking agents. Batch leaching studies of VCC materials were conducted with solutions representative of de-icer-contaminated road runoff at pH 8 and room temperature for 48 h. Ferrocyanide (FC) concentrations of 0 μM, 1 μM, 2 μM and 10 μM were tested with background electrolyte concentrations of 0.028 M NaCl (1000 mg/L Cl−) or 0.028 M NaClO4. Palladium release increased with FC concentration, ranging from 0.014 ± 0.002 μM Pd without FC to 5.013 ± 0.002 μM Pd at 10 μM FC. At 0 μM, 1 μM and 2 μM FC, chloride induced further Pd release, but had no effect at 10 μM FC. PHREEQC modeling predicted that the predominant species present in equilibrium with Pd(OH)2(s) were Pd(OH)20 and Pd(CN)42−, and that PdClx2−x complexes had only a minor effect on the total concentration of dissolved palladium. The effect of FC on Pd release was predicted but not the effect of Cl−, indicating possible kinetic control. Platinum was measured above limits of detection (LODs) only at 10 μM FC, and rhodium levels were below LODs, consistent with their slower complexation kinetics.
AB - Environmental levels of platinum group elements (PGEs) are rising due to emissions of vehicle catalytic converter (VCC) materials containing palladium, platinum and rhodium. When these PGE-containing VCC materials are exposed to soil and water, coordination complex formation with ligands present in the environment may mobilize PGEs into solution, particularly Pd. Road de-icing salt contains two ligands with high affinities for Pd2+: chloride (Cl−) from NaCl and cyanide (CN−) from ferrocyanide (Fe(CN)64−) anti-caking agents. Batch leaching studies of VCC materials were conducted with solutions representative of de-icer-contaminated road runoff at pH 8 and room temperature for 48 h. Ferrocyanide (FC) concentrations of 0 μM, 1 μM, 2 μM and 10 μM were tested with background electrolyte concentrations of 0.028 M NaCl (1000 mg/L Cl−) or 0.028 M NaClO4. Palladium release increased with FC concentration, ranging from 0.014 ± 0.002 μM Pd without FC to 5.013 ± 0.002 μM Pd at 10 μM FC. At 0 μM, 1 μM and 2 μM FC, chloride induced further Pd release, but had no effect at 10 μM FC. PHREEQC modeling predicted that the predominant species present in equilibrium with Pd(OH)2(s) were Pd(OH)20 and Pd(CN)42−, and that PdClx2−x complexes had only a minor effect on the total concentration of dissolved palladium. The effect of FC on Pd release was predicted but not the effect of Cl−, indicating possible kinetic control. Platinum was measured above limits of detection (LODs) only at 10 μM FC, and rhodium levels were below LODs, consistent with their slower complexation kinetics.
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U2 - 10.1016/j.chemosphere.2019.125578
DO - 10.1016/j.chemosphere.2019.125578
M3 - Article
C2 - 31864058
AN - SCOPUS:85076530380
SN - 0045-6535
VL - 245
JO - Chemosphere
JF - Chemosphere
M1 - 125578
ER -