Solubility and transport of platinum-group elements in supercritical fluids: summary and estimates of thermodynamic properties for ruthenium, rhodium, palladium, and platinum solids, aqueous ions, and complexes to 1000°C and 5 kbar

Sassani, David; Shock, Everett L.

doi:10.1016/s0016-7037(98)00049-0

Cited by 123 publications

(70 citation statements)

References 148 publications

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“…Pt(OH) 2 (aq) is the predominant dissolved species in a wide range of pH (1 < pH < 12). These observations are in agreement with the findings of Sassani & Shock (1998) and Byrne (2003) who concluded that hydroxide complexes could contribute significantly to the solubility of Pt in aqueous solutions.…”

Section: Pges In Watersupporting

confidence: 93%

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Complexation of platinum, palladium and rhodium with inorganic ligands in the environment

Colombo

Oates

Monhemius

et al. 2008

GEEA

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Platinum (Pt), palladium (Pd) and rhodium (Rh) are emitted by vehicle exhaust catalysts (VECs) and their concentrations have increased significantly in various environmental compartments, including airborne particulate matter, soil, roadside dust, vegetation, rivers and oceanic environments, over the last two decades as the use of VECs has increased. However, data on the chemical speciation of the platinum-group elements (PGEs) and their bioavailabilities are limited. In this paper, the thermodynamic computer model, HSC, has been used to predict the interactions of Pt, Pd and Rh with different inorganic ligands and to estimate the thermodynamic stability of these species in the environment. Eh-pH diagrams for the PGEs in aqueous systems under ambient conditions (25 C and 1 bar) in the presence of Cl, N and S species have been prepared. The results indicate that Pt, Pd and Rh can form complexes with all of the inorganic ions studied, suggesting that they are capable of mobilizing the PGEs as aqueous complexes that can be transported easily in environmental and biological systems and that are able to enter the food chain. Hydroxide species can contribute to the transport of PGEs in oxidizing environments such as road-runoff waters, freshwater, seawater and soil solutions, whereas bisulphide complexes could transport Pt and Pd in reducing environments. Ammonia species appear to be significant under near-neutral to basic oxidizing conditions. Chloride species are likely to be important under oxidizing, acidic and saline environments such as seawater and road-runoff waters in snowmelt conditions. Mixed ammonia-chloride species may also contribute to the transport of Pt and Pd in highly saline solutions.

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Section: Pges In Watersupporting

confidence: 93%

“…Wood et al (1992) and Sassani & Shock (1998) critically reviewed many investigations on the complexing of Pt and Pd by chloride. The various studies reported significantly different thermodynamic constants and the aforementioned authors disagree on which stability constants to recommend for both Pt and Pd-chloride complexes.…”

Section: Pge-n Systemmentioning

confidence: 99%

Complexation of platinum, palladium and rhodium with inorganic ligands in the environment

Colombo

Oates

Monhemius

et al. 2008

GEEA

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“…The overlap of the conditions of certain of our measurements with those of Wood (1991) allows us to reconsider these data and to propose consistent thermodynamic constants for PtOH + and Pt(OH) 2 0 as well as the Gibbs free energy of the aqueous species Pt 2+ (Table 4). A bibliographic review by Sassani and Shock (1998) of the available data reveals wide disagreement between the different sources. By using their semiempirical algorithms, these authors recalculated a value of ΔG f o (Pt 2+ ) of about +258.74 kJ/mol, which is higher than all the previous values determined from experiments (see appendix of Sassani and Shock, 1998).…”

Section: Discussionmentioning

confidence: 99%

“…A bibliographic review by Sassani and Shock (1998) of the available data reveals wide disagreement between the different sources. By using their semiempirical algorithms, these authors recalculated a value of ΔG f o (Pt 2+ ) of about +258.74 kJ/mol, which is higher than all the previous values determined from experiments (see appendix of Sassani and Shock, 1998). Table 4.…”

Section: Discussionmentioning

confidence: 99%

“…Recent measurements of the solubility of platinum and palladium (Gammons; Gammons; Pan; Wood and Gammons) have demonstrated the limit of these theoretical approaches for determining the stability constants of the aqueous complexes of precious metals. The recent attempt (Sassani and Shock, 1998) to compile data and estimate thermodynamic parameters of PGEs revealed shortcoming making it even more difficult to study the thermodynamic behaviour of PGEs in natural and industrial hydrosystems.…”

Section: Introductionmentioning

confidence: 99%

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Solubility of platinum in aqueous solutions at 25°C and pHs 4 to 10 under oxidizing conditions

Azaroual

Romand

Freyssinet

et al. 2001

Geochimica et Cosmochimica Acta

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Dissolution of Platinum in the Operational Range of Fuel Cells

et al. 2015

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One of the most important practical issues in low‐temperature fuel‐cell catalyst degradation is platinum dissolution. According to the literature, it initiates at 0.6–0.9 VRHE, whereas previous time‐ and potential‐resolved inductively coupled plasma mass spectrometry (ICP–MS) experiments, however, revealed dissolution onset at only 1.05 VRHE. In this manuscript, the apparent discrepancy is addressed by investigating bulk and nanoparticulated catalysts. It is shown that, given enough time for accumulation, traces of platinum can be detected at potentials as low as 0.85 VRHE. At these low potentials, anodic dissolution is the dominant process, whereas, at more positive potentials, more platinum dissolves during the oxide reduction after accumulation. Interestingly, the potential and time dissolution dependence is similar for both types of electrode. Dissolution processes are discussed with relevance to fuel‐cell operation and plausible dissolution mechanisms are considered.

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Solubility and transport of platinum-group elements in supercritical fluids: summary and estimates of thermodynamic properties for ruthenium, rhodium, palladium, and platinum solids, aqueous ions, and complexes to 1000°C and 5 kbar

Cited by 123 publications

References 148 publications

Complexation of platinum, palladium and rhodium with inorganic ligands in the environment

Complexation of platinum, palladium and rhodium with inorganic ligands in the environment

Solubility of platinum in aqueous solutions at 25°C and pHs 4 to 10 under oxidizing conditions

Dissolution of Platinum in the Operational Range of Fuel Cells

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