structural and chemical characterization of soot particles · 2020. 3. 13. · 2 03-july-2015...
TRANSCRIPT
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Structural and chemical characterization of soot particles
C. Focsa, I. K. Ortega, B. Chazallon, Y. Carpentier, C. Irimiea, M. Ziskind, C. Pirim, A. R. Ikhenazene, F.X. Ouf, F. Salm, D. Delhaye, D. Gaffié, J. Yon, D. Ferry
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Outline
• Motivation & framework
• Experimental techniques
• Results
• Conclusions
03-july-2015 Cambridge Particle Meeting2
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Motivation
Carcinogenic potential
Indirect effects,cloud formation
Environmental pollution
direct effects,radiation absorption
CLIMATE EFFECTS
HEALTH EFFECTS
SOOT: unburned residue of the combustion process
PAHs - adsorbed on the soot matrix
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Framework
• MERMOSE Project• Airplane soot
• Laboratory surrogates
• Project BIOTOX Project (Czech Republic, Russia)• Diesel and gasoline soot
• Different blends, motors, driving cycles…
• Field (road) collected samples (INERIS)
• Amadeus-Egide project (Vienna TU, Austria)• Biogenic aerosols, ice nucleation properties
• Secondary organic aerosols (ULCO, France)
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Framework
• MERMOSE Project•Airplane soot•Laboratory surrogates
• Project BIOTOX Project (Czech Republic, Russia)• Diesel and gasoline soot• Different blends, motors, driving cycles…• Field (road) collected samples (INERIS)
• Amadeus-Egide project (Vienna TU, Austria)• Biogenic aerosols, ice nucleation properties
• Secondary organic aerosols (ULCO, France)
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Project MERMOSE
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• Different regimes• 30%
• 70 %
• 85 %
• 100 %
Mini-CASTSAM 146Combustion chamber (M1)
PRELIMINARY RESULTS
• Different regimes• 7%
• 30%
• 70 %
• 71%
• 85 %
• 100 %
• Set points Sample Propane
(ml/min)Nitrogen(ml/min)
Oxidation(l/min)
Dilution(l/min)
SP-1 60 0 1.5 20
SP-2 60 0 1.15 20
SP-3 60 0 1 20
SP-A 50 200 1.2 2003-july-2015 Cambridge Particle Meeting
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• Airplane engine soot• SaM146 campaign : Mermose project
Four engine regimes: 30 %, 70%, 85%, 100%Sampled on quartz paper filters (Pallflex QAT-UP 2500)
and Si wafers
• Laboratory model soot• miniCAST soot - standard generator
Propane fuel various oxidation air flowsSampled on quartz paper and borosilicate filters
• Kerosene soot: laboratory diffusion flame (the same combustion conditions); sampled at different heights above the burner (HAB)
Airplane
CAST
Kerosene flame
Borosilicate filter
Ignition flat flame:methane 1.14 sLmair 10.9 sLm;
Diffusion flame: nitrogen 0.32 sLm,kerosene 180 g/h
Analyzed samples (a few examples)
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Experimental techniques• Measured properties: structure and surface chemical composition
• Techniques: Laser desorption/ionization mass spectrometry (L2MS), secondary ion mass spectrometry (SIMS) and Raman microscopy
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L2MS RamanSIMS
• High fragmentation
• High mass resolution
• Mapping, depth profiling
• Controlled fragmentation
• Ultra-sensitive to PAHs
• Selective (laser ionization)
• Non destructive
• Structural information
• Indirect chemical composition
03-july-2015 Cambridge Particle Meeting
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• Spectrum fit
• G band, ordered graphite (lorenztian)
• D1 band, disordered graphite,edges
• D2 band, disordered graphite,layers (lorenztian)
• D3 band, amorphous carbon (Gaussian
• D4 band, highly disordered graphite
• D1’ band, loosely bound PAHs (lorenztian)
Schmid et al., Anal. Chem. 2011
Raman Microscopy
• Excitation Wavelength• 514 nm
• 785 nm
• 50x objective, ~2 µm spot
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SaM146 soot structure, Raman + complementary analyses (NEXAFS, HR-TEM)
TEY-NEXAFS
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mini-CAST soot
D1’ band, loosely bond PAHs (Carpentier et al. A&A,548, 2012)
TEY-NEXAFS
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crystallite size, Raman vs TEM
• TEM
𝐿𝑎 𝑛𝑚 = (2.4 10−10)λ𝑙𝑎𝑠𝑒𝑟
4 ( 𝐼𝑑𝐼𝑔)
−1
• RAMAN
Layer edgesPerfectGraphite
Layer surface
Amorphuscarbon
Disordedgraphite, polyenes
Sample Size
30% 2.67 ± 0.30 nm
70% 2.85 ± 0.58 nm
85% 2.73 ± 0.45 nm
100% 3.06 ± 0.53 nm
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Raman fluorescence link to OC/TC
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Sample
Desorption
Ionization
Detection
Laser Desorption (LD) :
• IR OPO, = 2.5 4 µm, 10 ns, 10 Hz, Emax= 20 mJ/pulse
• Nd:YAG (1w – 4w), 10 ns, 10 Hz, Emax= 0.1 – 1 J/pulse
Laser Ionisation (LI) :
• 4th harmonic Nd:YAG, = 266 nm, 10 ns, 10 Hz, Emax= 100 mJ/pulse
• Tunable dye laser (225 – 900 nm, REMPI), 10 ns, 10 Hz
• NEW 118 nm source (9th harmonic Nd:YAG)
Detection :
Reflectron Time-of-Flight Mass Spectrometer(ReTOF-MS)
Chemical composition … L2MS
HAP SootIce (doped)
Laser Desorption / Laser Ionization / Time-of-Flight Mass Spectrometry
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L2MS Performances
Mass detected typically up to 800 Th (for soot)
Mass resolution ~1000
High sensitivity to PAHs … LOD ~ 10 attomol per laser shot (~10-6 ML)
thanks to the resonant absorption at 266 nm (REMPI)
Control the fragmentation degree
Control the desorption depth
(Semi)quantitative approach possible
through external standard calibration,
ionization cross section corrections
Pyrene / activated carbon,
9.52∙10-8 mol/g, 600 m2/g
Faccinetto et al.,
Combust. Flame, 158, 227 (2011)
Environ. Sci. Technol. 2015, submitted
03-july-2015 Cambridge Particle Meeting15
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• Alkyl-PAHs
50 100 150 200 250 300
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
91
165
228
244
120
170
1461
06 192
276132
178
1561
42
128
118
104
92
262
78
248
234
230
220
216
202
206
189
No
rma
lize
d in
ten
sity
m/z IVECO 1500 rpm hot TQ36 B30
Cn+6
H2n+6
Cn-benzene
Cn+8
H2n+8
Cn-styrene
Cn+10
H2n+8
Cn-naphthalene
Cn+14
H2n+10
Cn-anthracene/phenanthrene
Cn+16
H2n+10
Cn-pyrene/fluoranthene
0.0
0.2
0.4
0.6
0.8
1.0
Diesel IVECO
engine exhaust (TQ36)
alkylphenanthrene series
alkylpyrene series
50 100 150 200 250 300 350
0.0
0.2
0.4
0.6
0.8
1.0
No
rma
lize
d in
ten
sity
Gasoline
engine exhaust (KR12)
No
rma
lize
d in
ten
sity
m/z
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L2MS
Chemical composition, diesel and gasoline soot (PRELIMINARY)
BIOTOX Project
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0,0
0,5
1,0
0,0
0,5
1,0
50 100 150 200 250 300 350 400
0,0
0,5
1,0
THE38_70%x 75
x 75
No
rma
lize
d in
ten
sity
THE37_85%
x 75
m/z (amu)
THE36_100%
TOF-SIMS
Chemical composition, Mass spectrometry
• PAH and derivatives, aliphatic, organo-sulfates, metals, …
• PCA, mass defect (SIMS … high resolution)
Thermo-optical analysis, Sunset Lab, protocol IMPROVE (FX Ouf, IRSN)
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SaM 146
Airplane soot, SaM 146 campaign
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m/z
I [a
.u.]
SP2
202
202 L2MS
SIMS
SIMS2 zones
L2MS4 zones
Chemical composition, CAST soot: L2MS & SIMS
03-july-2015 Cambridge Particle Meeting18
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Mo4On-
Chemical composition, Heavy metals in airplane soot samples
SiO2- ; Mo2O6
- ; HSO4-
Fe+ ; Si+; Na+
• Molybdenum • Iron
03-july-2015 Cambridge Particle Meeting19
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Chemical composition, diesel and gasoline soot
• Sulfur containing compounds
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BIOTOX Project (PRELIMINARY)
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Preliminary Ice nucleation studies
Preliminary results:
• Ice nucleation properties of CAST soot particles depend on the collection set-point• Soot aging influence … ?• Link to structure & chemical composition …
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Conclusions
• Airplane soot from both campaigns (SaM 146 & M1) have similar structure … independent of engine regime ?
• High OC at low engine regime … MS total PAH as good indicator of OC/TC … also fluorescence ?
• Higher amount of sulfur in M1 samples compared to SaM146 … link to combustion geometry?
• Heavy metals in oil droplets … coming from engine gear ?
• Starting ice nucleation studies on airplane soot and surrogates
• Best surrogate for airplane soot is obtained using CAST SP-1 working point … low/high engine regime … mimicked properties ?
03-july-2015 Cambridge Particle Meeting22
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Thanks for your attention
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Conclusions, chemical composition
• Airplane samples present a relatively low amount of PAHs, When compared to CAST, SP-1 set point is closer to airplane samples in PAHs distribution
• SAM 146 samples present lower amounts of sulfur than M1 samples, CAST samples present negligible amounts of sulfur
• Heavy metals are found in SAM 146 samples, but seems associated with oil droplets, and most likely are coming from motor gear
03-july-2015 Cambridge Particle Meeting20
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Motivation
03-july-2015 Cambridge Particle Meeting
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Chemical composition, diesel and gasoline soot (PRELIMINARY)
• Alkyl-PAHs
50 100 150 200 250 300
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
91
165
228
244
120
170
1461
06 192
276132
178
1561
42
128
118
104
92
262
78
248
234
230
220
216
202
206
189
No
rma
lize
d in
ten
sity
m/z IVECO 1500 rpm hot TQ36 B30
Cn+6
H2n+6
Cn-benzene
Cn+8
H2n+8
Cn-styrene
Cn+10
H2n+8
Cn-naphthalene
Cn+14
H2n+10
Cn-anthracene/phenanthrene
Cn+16
H2n+10
Cn-pyrene/fluoranthene
0.0
0.2
0.4
0.6
0.8
1.0
Diesel IVECO
engine exhaust (TQ36)
alkylphenanthrene series
alkylpyrene series
50 100 150 200 250 300 350
0.0
0.2
0.4
0.6
0.8
1.0
No
rma
lize
d in
ten
sity
Gasoline
engine exhaust (KR12)
No
rma
lize
d in
ten
sity
m/z
03-july-2015 Cambridge Particle Meeting17
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15-june-2015 AT2105-Tampere27
Chemical composition, CAST soot: L2MS & Raman
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Spectrum interpretation
15-june-2015 AT2105-Tampere28
G band• Characteristic of crystalline
graphite/graphene
• G band intensity decreases when the number of defect increases
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Spectrum interpretation
D1 band• Ring breathing forbidden by symmetry in
crystalline graphite
• Presence of defects breaks the symmetry, allowing the observation of this mode
• Intensity increases with defects until a limit
Eckmann et al. , Nano Letters, 12, 2012
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Spectrum interpretation
D2 band• Mode related to edge carbons
• D2 band intensity proportional to the number of edge carbons, thus related to vacancy defects
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Spectrum interpretation
D3 band• Traditionally associated with amorphous
carbon
• Might be related to graphitic carbon as well
• Associated with small crystalline domains
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Spectrum interpretation
D4 band• Mode related to impurities not to graphite
layers (independent of defects)
• In our case, D4 most likely correspond to polyen chains attached to the edge of graphite crystallites
• Only found in soot and char