structural and chemical characterization of soot particles · 2020. 3. 13. · 2 03-july-2015...

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

Outline

• Motivation & framework

• Experimental techniques

• Results

• Conclusions

03-july-2015 Cambridge Particle Meeting2

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


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)

4 03-july-2015 Cambridge Particle Meeting

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)


Project MERMOSE

6

• 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

• 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)


Experimental techniques• Measured properties: structure and surface chemical composition

• Techniques: Laser desorption/ionization mass spectrometry (L2MS), secondary ion mass spectrometry (SIMS) and Raman microscopy

8

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

• 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


SaM146 soot structure, Raman + complementary analyses (NEXAFS, HR-TEM)

TEY-NEXAFS


mini-CAST soot

D1’ band, loosely bond PAHs (Carpentier et al. A&A,548, 2012)

TEY-NEXAFS


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


Raman fluorescence link to OC/TC


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


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


• 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


L2MS

Chemical composition, diesel and gasoline soot (PRELIMINARY)

BIOTOX Project

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)


SaM 146

Airplane soot, SaM 146 campaign

m/z

I [a

.u.]

SP2

202

202 L2MS

SIMS

SIMS2 zones

L2MS4 zones

Chemical composition, CAST soot: L2MS & SIMS


Mo4On-

Chemical composition, Heavy metals in airplane soot samples

SiO2- ; Mo2O6

- ; HSO4-

Fe+ ; Si+; Na+

• Molybdenum • Iron


Chemical composition, diesel and gasoline soot

• Sulfur containing compounds


BIOTOX Project (PRELIMINARY)

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 …


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 ?


Thanks for your attention

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


Motivation

03-july-2015 Cambridge Particle Meeting

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


15-june-2015 AT2105-Tampere27

Chemical composition, CAST soot: L2MS & Raman

Spectrum interpretation

15-june-2015 AT2105-Tampere28

G band• Characteristic of crystalline

graphite/graphene

• G band intensity decreases when the number of defect increases


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


D2 band• Mode related to edge carbons

• D2 band intensity proportional to the number of edge carbons, thus related to vacancy defects


D3 band• Traditionally associated with amorphous

carbon

• Might be related to graphitic carbon as well

• Associated with small crystalline domains


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

structural and chemical characterization of soot particles · 2020. 3. 13. · 2 03-july-2015...

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