Chemical Composition of Diesel/Biodiesel Particulate Exhaust by FTIR Spectroscopy and Mass Spectrometry: Impact of Fuel and Driving Cycle

Abstract

The growing concern about air quality and the impact exhaust particles can have on the environment has resulted in the increased use of alternative fuels. A sampling campaign from a conventional heavy diesel engine operated in typical transient cycle or steady-state condition, and running on diesel, 30% biodiesel in diesel, and 100% biodiesel was carried out. The particulate composition was characterized using Fourier Transform Infrared (FTIR) spectroscopy, Two-step Laser Mass Spectrometry (L2MS), Secondary Ion Mass Spectrometry (SIMS), thermo-optical analysis, and capillary electrophoresis. Elemental carbon is demonstrated to decrease from diesel to 100% biodiesel, in agreement with the evolution of aromatic bands and the MS abundance of C n -fragments, while organic carbon exhibits a constant level irrespective of the working regime. Aliphatic, aromatic, carboxyl, carbonyl, hydroxyl functionalities, and nitro compounds are found to depend on the engine-working regime. Mass spectra are mainly characterized by alkyl fragments (C n H 2n+1 + ), associated to normal and branched alkanes, PAHs and their alkylated derivatives. The addition of biodiesel to diesel changes the particulate composition towards more oxygenated constituents, such as carbonyl groups attributed to methyl ester CH 3 O + fragments of unburned biodiesel. Fuel-specific fragments have been identified, such as C 3 H 7 O + for diesel, and C 2 H 3 O 2 + and CH 3 O -for biodiesel. Nitrogenized compounds are revealed by -NO 2 functionalities and N-containing fragments. Principal Component Analysis (PCA) was successfully applied to discriminate the engine operating conditions, with a higher variance given by the fuel, thus allowing to better evaluate the environmental impacts of alternative energy source emissions.

Accumulation and coarse mode aerosol concentrations and carbonaceous contents in the urban background atmosphere in Amman, Jordan

“…According to the ATR-FTIR analysis, the spectra showed three interesting major signals (Fig. 7) for carbon containing compounds that are emitted from fossil fuel combustion such as traffic tailpipe emissions (e.g., Siciliano et al 2018;Popovicheva et al 2017;Shaltout et al 2016;Agudelo-Castañeda et al 2015;Popovicheva et al 2015;Jiang et al 2011). The first signal (wave number 800-1100 cm −1 ; mass fraction 37.1-45.6%) represents polycyclic aromatic hydrocarbon compounds that contain functional groups such as sulfur, hydroxyl, or ester.…”

Chemical Compositions of PM2.5 Emitted from Diesel Trucks and Construction Equipment

“…collected the vehicle exhaust samples near the diesel bus terminals in Colorado and found that carbon fraction accounted over 95% in PM 2.5 . Popovicheva et al (2017) tested a heavy diesel engine in different driving conditions using alternative diesel fuels. Cheng et al (2010) measured tunnel and roadside PM emissions of on-road vehicles in Hong Kong during 2003, and calculated emission factor (EF) of diesel and non-dieselfueled vehicles.…”

Model Guided Application for Investigating Particle Number (PN) Emissions in GDI Spark Ignition Engines

“…Organic compounds are defined as all the organic species (aromatic or aliphatic molecules and their fragments) that are detected in the positive polarity spectra. Carbon clusters Cnare considered to be a marker for elemental carbon [49,50,51] and form the second group. All the inorganic species, with the exception of sulphur-bearing compounds, were interpreted as ash (metals).…”