Abstract:

The effects of solar irradiation on an asphalt binder were investigated. Upon irradiation in a photooxidation microcosm, thin films of the asphalt binder produced abundant oil- and water-soluble oxygenated hydrocarbons, which are hypothesized to leached from roads and highways through photooxidation reactions. Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) enabled extensive compositional characterization of the virgin asphalt binder, irradiated asphalt binder, and the water-soluble photoproducts. The results revealed 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 confirmed photo-induced oxidation, fragmentation, and potentially polymerization as active processes involved in the production of water-soluble organic pollutants from asphalt.

Suggested Citation:

Niles, Sydney F., Martha L. Chacon-Patino, Alan G. Marshall, and Ryan P. Rodgers. 2021. Characterization of an asphalt binder and photoproducts by Fourier transform ion cyclotron resonance mass spectrometry reveals abundant water-soluble hydrocarbons. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/RYXAQDA0

Purpose:

The purpose of this study was to provide molecular level characterization for water-soluble organic species which are leached from road asphalt in the environment following solar irradiation from sunlight. Additionally, the amount of water-soluble organic material leached as a function of irradiation time was quantified.

Data Parameters and Units:

Legend Number of Peaks = Number of Peaks on Full Spectrum with signal magnitude greater than six times the baseline root-mean square noise % R. A. = Percent Relative Abundance DBE = double bond equivalents - number of aromatic rings plus double bonds to carbon % R. A.(No Hits Discarded) = Percent Relative Abundance with Non Classified Peaks Removed A. M. W. average = Relative abundance weighted average molecular weight A.W. average C# = relative abundance weighted average carbon number A.W. average DBE = average number of double bond equivalents A.W. average H/C = relative abundance weighted average hydrogen-to-carbon ratio A.W. average O/C = relative abundance weighted average oxygen-to-carbon ratio A.W. average N/C = relative abundance weighted average nitrogen-to-carbon ratio Sum R. A. = Sum of Relative Abundance for all mass spectral peaks RMS Error = Root Mean Square Error PosESI = Positive Electrospray Ionization NegESI = Negative ion Electrospray Ionization APPI = Atmospheric Pressure Photoionization

Methods:

(+) atmospheric photoionization (APPI) FT-ICR MS and (-) electrospray ionization (ESI) FT-ICR MS were used to characterize the virgin asphalt binder, irradiated asphalt binder, and water-soluble organic species from irradiated asphalt. A priority pollutant (PPL) extraction was conducted for isolation of water soluble organics.

Instruments:

9.4 Tesla Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS)

Individual Files: