Department of Chemistry and Biochemistry, Florida State University, 95 Chieftain Way, Tallahassee, Florida 32306, United States.
Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.
Environ Sci Technol. 2020 Jul 21;54(14):8830-8836. doi: 10.1021/acs.est.0c02263. Epub 2020 Jul 8.
Road asphalt is comprised of aggregate (rocks) mixed with a binder composed of high-boiling petroleum-derived compounds, which have been thought to be relatively inert (unreactive) and thus leach small amounts of polyaromatic hydrocarbons (PAHs) into water from the built environment. However, recent studies have demonstrated that petroleum readily undergoes photooxidation and generates water-soluble oxygen-containing hydrocarbons. Therefore, here, we investigate the effects of solar irradiation on an asphalt binder. Upon irradiation in a photooxidation microcosm, thin films of the asphalt binder produce abundant oil- and water-soluble oxygenated hydrocarbons, which we hypothesize are also leached from roads and highways through photooxidation reactions. Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) enables extensive compositional characterization of the virgin asphalt binder, irradiated asphalt binder, and the water-soluble photoproducts. The results reveal the production of water-soluble species that resemble the molecular composition of petroleum-derived dissolved organic matter, including abundant hydrocarbons and S-containing species with up to 18 oxygen atoms. The results also confirm photo-induced oxidation, fragmentation, and potentially polymerization as active processes involved in the production of water-soluble organic pollutants from asphalt.
道路沥青由骨料（岩石）与由高沸点石油衍生化合物组成的粘合剂混合而成，这些化合物被认为相对惰性（无反应性），因此会从建筑环境中少量浸出多环芳烃（PAHs）到水中。然而，最近的研究表明，石油很容易发生光氧化，并生成水溶性含氧烃。因此，在这里，我们研究了太阳辐射对沥青粘合剂的影响。在光氧化微环境中辐照时，沥青粘合剂的薄膜会产生大量的油溶性和水溶性含氧烃，我们假设这些烃也是通过光氧化反应从道路和高速公路中浸出的。超高分辨率傅里叶变换离子回旋共振质谱（FT-ICR MS）能够广泛地表征原始沥青粘合剂、辐照沥青粘合剂和水溶性光产物的组成。结果表明，会产生类似于石油衍生溶解有机质的分子组成的水溶性物质，包括丰富的碳氢化合物和多达 18 个氧原子的含 S 物质。结果还证实了光诱导氧化、碎片化和潜在聚合是沥青中产生水溶性有机污染物的活跃过程。
