FTIR analysis of surface functionalities on particulate matter produced by off-road diesel engines operating on diesel and biofuel

Environ Sci Pollut Res Int. 2015 Mar;22(6):4534-44. doi: 10.1007/s11356-014-3688-8. Epub 2014 Oct 16.

Abstract

Fourier transform infrared spectroscopy is applied as a powerful analytic technique for the evaluation of the chemical composition of combustion aerosols emitted by off-road engines fuelled by diesel and biofuels. Particles produced by burning diesel, heated rapeseed oil (RO), RO with ethylhexylnitrate, and heated palm oil were sampled from exhausts of representative in-use diesel engines. Multicomponent composition of diesel and biofuel particles reveal the chemistry related to a variety of functional groups containing carbon, hydrogen, oxygen, sulfur, and nitrogen. The most intensive functionalities of diesel particles are saturated C-C-H and unsaturated C=C-H aliphatic groups in alkanes and alkenes, aromatic C=C and C=C-H groups in polyaromatics, as well as sulfates and nitrated ions. The distinguished features of biofuel particles were carbonyl C=O groups in carboxylic acids, ketones, aldehydes, esters, and lactones. NO2, C-N and -NH groups in nitrocompounds and amines are found to dominate biofuel particles. Group identification is confirmed by complementary measurements of organic carbon (OC), elemental carbon, and water-soluble ion species. The relationship between infrared bands of polar oxygenated and non-polar aliphatic functionalities indicates the higher extent of the surface oxidation of biofuel particles. Findings provide functional markers of organic surface structure of off-road diesel emission, allowing for a better evaluation of relation between engine, fuel, operation condition, and particle composition, thus improving the quantification of environmental impacts of alternative energy source emissions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aerosols / analysis
  • Air Pollutants / analysis*
  • Biofuels / adverse effects
  • Biofuels / analysis*
  • Environmental Monitoring / methods*
  • Environmental Monitoring / statistics & numerical data
  • Fatty Acids, Monounsaturated
  • Gasoline / adverse effects
  • Gasoline / analysis*
  • Oxidation-Reduction
  • Palm Oil
  • Particulate Matter / analysis*
  • Plant Oils / analysis
  • Rapeseed Oil
  • Spectroscopy, Fourier Transform Infrared
  • Vehicle Emissions / analysis*

Substances

  • Aerosols
  • Air Pollutants
  • Biofuels
  • Fatty Acids, Monounsaturated
  • Gasoline
  • Particulate Matter
  • Plant Oils
  • Rapeseed Oil
  • Vehicle Emissions
  • Palm Oil