Abstract View
Molecular Characterization of Aerosolized Bio-Oil
EMILY HALPERN, Christopher West, Anusha P.S. Hettiyadura, Alexander Laskin, Purdue University
Abstract Number: 335
Working Group: Carbonaceous Aerosol
Abstract
The chemical characterization of various volatility-separated fractions of bio-oils is very challenging due to the complexity of the mixture and the range of physicochemical properties of the components. It is essential to classify bio-oil components with respect to their major chemical types and functional groups to inform the deoxygenation processing of crude bio-oil surrogates and their viability as an energy source. Due to the range of volatilities of the molecular components, fractionation of the bulk bio-oil can be used to modify the composition so that it contains only components of interest. Here, we investigate aerosolized bio-oil fractions when deposited onto the different stages of a Microorifice Uniform Deposit Impactor (MOUDI), where fractionation was achieved by aerosol size-segregation and consequently reduced pressures on each of the stages. The molecular characterization of the bio-oil fractions was achieved using ultrahigh performance liquid chromatography equipped with a photodiode array detector and high-resolution mass spectrometry (UHPLC-PDA-HRMS) with both electrospray ionization (ESI) and dopant-assisted atmospheric pressure photoionization (APPI). Molecular characterization allowed description of the individual species present in the bio-oil sample based on estimated values of volatility, glass transition temperature, aromaticity, and elemental ratios. By comparing the mass absorption coefficients of bio-oil fractions with different volatilities, we were able to show that the less volatile fractions absorb more than the bulk sample due to the evaporation of volatile compounds at lower pressures in the MOUDI. This work provides insight on the molecular components of representative bio-oils and provides an opportunity to improve design and engineering of novel bio-oil fuels.