Platinum group elements study in automobile catalysts and exhaust gas samples
Mehrazin Omrani1, Mathieu Goriaux1, Yao Liu1
1IFSTTAR, GERS, EE, F-44344 Bouguenais, France; IRSTV, FR CNRS 2488, 44321 Nantes Cedex 3, France.
Environmental Pollution (Barking, Essex : 1987)
|November 26, 2019
Summary
Automotive catalytic converters release Platinum-Group Elements (PGEs) like platinum, palladium, and rhodium into the environment as they degrade. Older vehicles and cold starts contribute to higher PGE emissions, with newer cars showing increased release during high-speed driving.
Area of Science:
- Environmental Science
- Analytical Chemistry
- Materials Science
Background:
- Platinum-Group Elements (PGEs) are critical components in automotive catalytic converters for emission control.
- Degradation of catalytic converters leads to the release of PGEs into urban environments.
- Understanding PGE emission factors is crucial for assessing environmental impact.
Purpose of the Study:
- To quantify Platinum-Group Element (PGE) content in used catalytic converters.
- To determine PGE emission factors from various vehicle emission standards (Euro 3-6) and driving conditions.
- To investigate the relationship between vehicle age, technology, and PGE emissions.
Main Methods:
- Analysis of PGE content (Pt, Pd, Rh) in three gasoline 3-way catalytic converters with varying mileage.
- Monitoring of PGE emission factors in exhaust gases from Euro 3, 4, 5, and 6 gasoline and diesel vehicles.
- Comparison of emissions across different vehicle types, emission standards, and driving cycles (urban, motorway, cold start).
Main Results:
- Catalytic converters contained PGEs in ranges of 6-511 mg/kg for Pt, 0.5-2507 mg/kg for Pd, and 0.1-312 mg/kg for Rh.
- A shift from Platinum (Pt) to Palladium (Pd) was observed in more recent catalytic converters.
- Exhaust emissions measured up to 36.5 ± 3.8 ng/km for Pt, 8.9 ± 1.1 ng/km for Pd, and 14.1 ± 1.5 ng/km for Rh.
- Higher PGE emissions were linked to older vehicles (Euro 3), urban driving in Euro 3-4 diesel vehicles, cold starts, and motorway driving in newer vehicles.
Conclusions:
- Catalytic converter wear and tear is a significant source of environmental PGE pollution.
- Vehicle emission standards and driving conditions substantially influence PGE release.
- Older vehicle technology and specific driving scenarios (cold start, high speed) exacerbate PGE emissions.
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