Emission and Collection of Polycyclic Aromatic Hydrocarbons From Raw Asphalt Samples Heated at 130 °C

Abstract

The emission and collection of polycyclic aromatic hydrocarbons (PAHs) in the aqueous solution and asphalt samples obtained from different refineries in Brazil were evaluated. The aqueous solution and asphalt samples were heated under an argon atmosphere at 50 and 130 °C, respectively, for 60 min in a closed system. The targeted PAHs for the aqueous solution were acenaphthene, anthracene, and fluoranthene, while those for the asphalt samples were naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]anthracene. These were all taken from the US EPA list. The performances of Amberlite XAD-2, high-density polyethylene (HDPE), silica (Si), polyurethane foam (PUF), and granular activated carbon (GAC) in collecting the PAHs from the vapor phase by gas−solid adsorption were compared. High-performance liquid chromatography with a diode array detector was used to quantify the mixtures of PAHs retained by the adsorbents. PUF and XAD-2 had the highest PAH retention capacity. For the aqueous solution, PUF showed adsorption yields of 100% for all the investigated PAHs. XAD-2 was also a good adsorbent (adsorption yields >90%), followed by HDPE (75−90% adsorption yields). For silica and GAC, the adsorption yields depended strongly on the PAHs. Alternatively, for the asphalt samples, the adsorption yield decreased dramatically for all the evaluated PAHs, showing that the asphalt matrix had a strong influence on the adsorption capacity of the adsorbents. In this case, the total PAH retention was 47.2% for PUF, 46.8% for XAD-2, 29.9% for GAC, 27.3% for Si, and 19.8% for HDPE. The retention/elution processes on the adsorbent surfaces were also evaluated by atomic force microscopy.

Diagnóstico de emissões de poluentes atmosféricos na produção de misturas asfálticas

“…A literatura aponta que os HPAs de pesos moleculares mais baixos, com dois ou três anéis aromáticos, são mais voláteis e, por isso, são emitidos a priori na fase gasosa, o que justificaria os baixos níveis de COVs e HPAs com até 3 anéis, como: naftaleno, acenafteno e acenaftileno, adsorvidos na fase particulada em análise (Ravindra, Sokhi e Van Grieken, 2008;Brudi et al, 2020). Pode-se seguir a mesma compreensão para os HPAs de maior peso molecular.…”

Emission Characteristics, Environmental Impacts, and Health Risks of Volatile Organic Compounds from Asphalt Materials: A State-of-the-Art Review

“…6 When heated to temperatures of 140−180 °C, necessary for fluidity during construction operations, volatile organic compounds (VOCs) can volatilize from hot asphalt into the atmosphere. 7,8 Research has identified significantly heightened levels of VOCs, such as benzene, toluene, ethylbenzene, and xylene, in the vicinity of asphalt mixing plants, storage tanks, and paving sites compared to background ambient conditions. 9,10 Subsequently released into the atmosphere, VOCs engage in photochemical reactions that produce ozone, fine particulate matter, and secondary organic aerosol (SOA), which degrade regional air quality and contribute to climate change.…”

“…However, mounting concerns have emerged regarding the potential effects of asphalt materials on air quality and human health during high-temperature mixing, transportation, and paving processes. , Asphalt binders are derived from the distillation and fractionation of crude oils, resulting in a complex mixture of thousands of hydrocarbon components . When heated to temperatures of 140–180 °C, necessary for fluidity during construction operations, volatile organic compounds (VOCs) can volatilize from hot asphalt into the atmosphere. , Research has identified significantly heightened levels of VOCs, such as benzene, toluene, ethylbenzene, and xylene, in the vicinity of asphalt mixing plants, storage tanks, and paving sites compared to background ambient conditions. , Subsequently released into the atmosphere, VOCs engage in photochemical reactions that produce ozone, fine particulate matter, and secondary organic aerosol (SOA), which degrade regional air quality and contribute to climate change . Consequently, VOC emissions from asphalt materials have posed substantial threats to both the atmospheric environment and human health.…”