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

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.

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

“…FTIR spectra of filter samples were acquired using an IRPrestige-21 spectrometer (Shimadzu, Japan) in diffuse reflection mode described in details elsewhere (Popovicheva et al, 2015b(Popovicheva et al, , 2016. Spectra were recorded in the 450 to 4000 cm -1 range with 4 cm -1 resolution and 100 accumulated scans.…”

“…Biofuel particles exhibit specific chemical signatures, such as functional groups in carboxylic acids, ketones, esters, and -NO 2 , C-N, and -NH groups in nitro compounds. In addition, surface oxidation in biofuel particles is suggested by the presence of polar oxygenated and non-polar aliphatic functionalities (Popovicheva et al, 2015b). Therefore, the addition of biodiesel to fuel blends, such as methyl ester oils, leads to significant increase of carbonyl, PAH, nitro-PAH, and oxy-PAH compounds .…”

Aerosol Pollutants during Agricultural Biomass Burning: A Case Study in Ba Vi Region in Hanoi, Vietnam

“…The functionalities of traffic emissions demonstrate a different pattern due to absorption of aromatic C = C and aliphatic C-C-H groups at 1596 cm -1 and 2922-2850 cm -1 , respectively, typical for diesel/gasoline emissions (Popovicheva et al, 2015b) ) ions (Fig. 4(a)).…”

Applications of Infrared Spectroscopy in Analysis of Organic Aerosols

“…A comprehensive interpretation of FTIR spectra has been tabulated in Aliphatic carboxylic acids (OH) and Amino acids/Amines (OH) [12] 3500 -2500 Carbohydrates (C-OH) [12] 3500 -3100 Organic hydroxyl (C-OH) [19] 3440 -3400 Hydroxyl (-OH) [30] 3400 -2500 Carboxylic acid (OH) [45] 3400-2400 Carboxylic acid (OH stretch) [24] [ 44] 3400, 1440 -1220, 1260 -1000 Alcohol and phenol [44] 3400, 1625 Amine (NH 2 ) [19] [20] 3400 OH stretching of phenol hydroxyl and carboxyl [5] 3382 -3323 Alcohol (OH) [45] 3380 H-bonding of hydroxyl [46] 3350, 1350, 650 ± 50 Alcohols/Phenols (OH) [12] 3350 -3205 Alcohol COH [24] 3350, 3180 Primary amide N-H stretch [44] 3300 -3150 Alcohol groups [33] 3300 -2900 C-H stretching in alkane, alkene, alkyne, aromatic [44] 3300 Secondary amide N-H stretch [44] 3300 Hydrogen bonded [8] 3200 -3000, 1290 -1000 Aromatic carbon (Arom-H) [38] G. 3200 -3000 Aromatic carbons (Arom-H) [36] 3130 -3030, 900 -670 Aromatic (C=C-H) [48] 3100 -3070 Carboxylic acid (COOH) [30] 3100 -3000 Aromatic (C-H) [42] 3100 -2900 Unsaturated aliphatic (C=C-H) [17] [19] [20] 3100 -3000 Alkene (C-H) [38] 3100 -3000 Aromatic (C=C-H) [17] [19] [20] 3100 -3000 Unsaturated aliphatic (C=C-H) [48] 3100 -3000 Unsaturated and aromatic (C-H) [12] 3100 H-bonding of organic acid [46] 3100 -2900 Alkane groups [33] 3090 -3075, 3050 -3000, 990 -815 Aliphatic Hydrocarbons (C-H) [12] 3050 Aromatic (C-H) [24] [ …”

“…1710 -1680 Aromatic polycarboxylic acids (C=O) [12] 1706 C=O in aldehydes and ketones [55] 1700 Carbonyl (C=O) [54] 1690 -1680 Hydrogen bonded (O-H) [8] 1680 -1665, 1660 -1630 Aliphatic hydrocarbons (C=C) [12] 1680 -1630 C=O stretch in amide [44] 1680 -1620 Unsaturated aliphatic (C=C) [48] 1650 -1620 Alkenyl double bond stretch (C=C) [10] 1650 -1590 Amino (C-NH 2 ) [48] 1644, 1281, 849 O-N groups [31] 1640 -1560 N-H bend in primary amines [44] 1640 -1550 Primary and secondary amide N-H bend [44] 1440 -1220 Alcohol and phenol (C-O-H bend) [44] 1400 -1390 C-H deformation of CH 3 groups [52] 1400 OH in carbohydrates [12] 1400 C-H in carbohydrates [12] 1350 -1340 Nitro-aromatic (NO 2 ) [42] 1350 -1000 C-N stretch in amines [44] 1340 -1250 Aromatic (C-N) [48] 1320 -1210 Aliphatic carboxylic acids (CO) [12] 1320 -1210 Amino acids/Amines (CO) [12] 1300 -1100 Ketone C (C=O)C bend [44] 1300-1000 C-O stretch in ether, ester [44] 1298 -1200 Organonitrates [46] 1286, 1249, 1222 -CH 2 wagging [50] 1280 Organonitrate [41] 1280 -1278, 1631 Organonitrate [53] 1280 -1270 Organonitrate (ONO 2 ) [42] 1280 -1210 Esters/ethers/phenols (C-O) [7] 1280 -1137 C-O stretching of esters, ethers and phenols [52] 1280 Symmetric NO 2 stretch in organonitrate [44] G. 1260 -700 Alkane skeletal vibration (C-C) [38] 1220 C-O stretching and O-H bending vibrations of COOH [5] 1210 -1160, 1100 -1030 Esters/Lactones (C-C-O) [12] 1200 -900 Carbohydrates (C-O-C) [12] 1182 C-O-C stretching …”