Performance Parameters of Inductively Coupled Plasma Optical Emission Spectrometry and Graphite Furnace Atomic Absorption Spectrometry Techniques for Pd and Pt Determination in Automotive Catalysts

Abstract

Palladium (Pd) and platinum (Pt) are extensively used as catalysts in the petrochemical and automotive industries, and due to high demand for them on the market, their recycling from spent supported catalysts is clearly needed. To assess the content of Pd and Pt in catalysts in order to establish their commercial value or to evaluate the recovery efficiency of technologies used for recycling, reliable analytical methods for determination of these elements are required. Spectrometric methods, such as inductively coupled plasma optical emission spectrometry (ICP-OES) and graphite furnace atomic absorption spectrometry (GFAAS) are powerful tools that can be employed for the determination of Pd and Pt in various sample matrices. However, these methods allow only the injection of liquid samples. In this regard, the digestion of solid sample by microwave-assisted acid extraction procedures at high pressures and temperatures is often used. In this study, a microwave acid digestion method was optimized for the extraction of Pd and Pt from spent catalysts, using a four-step program, at a maximum 200 °C. The resulting solutions were analyzed using ICP-OES, at two different wavelengths for each metal (Pd at 340.458 and 363.470 nm, and Pt at 265.945 and 214.423 nm, respectively) and using GFAAS (Pd at 247.64 nm, Pt at 265.94 nm). Five types of spent catalyst were analyzed and the standard deviations of repeatability for five parallel samples were less than predicted relative standard deviations (PRSD%) calculated using Horvitz’s equation for all the analyzed samples.

A new preconcentration technique for the determination of PGMs and gold by fire assay and ICP-OES

“…Accurate determination of these metals requires the use of highly sensitive analytical instruments. Because of its sensitivity and capability to measure traces, ICP-OES has been successfully employed to fully characterize PGMs and Au in geological materials and automotive catalysts (Senila et al, 2020). In addition, a variety Nickel sulphide collection and sodium peroxide fusion followed by Te co-precipitation are a common method for PGM analysis (Balcerzak, 2002).…”

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and materials

“…For example, an ‘optimized’ microwave extraction procedure for determination of Pd in Pt in spent auto catalysts by ICP-OES and GFAAS failed to enthuse this author. 117 Preconcentration methods continue to be reported to allow reduced limits of detection. Zhang et al described a bismuth fire assay method for the preconcentration of precious metals for analysis using ICP-OES.…”

Inductively coupled plasma time-of-flight mass spectrometry (ICP-TOFMS) with desolvating sample introduction and He collision gas for high-accuracy determination of Rh, Pd and Pt in automobile catalytic converters

“…18,19 Three more used automobile catalyst CRMs were characterised primarily with ICP-OES providing concentrations of Pd, Pt and Rh with similarly low uncertainty. [20][21][22] The matrix in a used catalyst is very different from that in an unused catalyst as the former may contain contaminants deriving from fuel, oil and their additives such as carbon (e.g., 2-4 wt%), 21,23 sulphur, lead, manganese, phosphorus and so on. 24 Industry ideally requires both types of CRMs to check that the analytical methods used are equally applicable to both types of material.…”