Bourrous, S.

Fauvel, S.

Kort, A.

Lintis, L.

Nuvoli, J.

Ouf, F.-X

Yon, J.

English

Yon, Jerôme

Hal-Diderot

True density of soot particles: A comparison of results highlighting the influence of the organic contents

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True density of soot particles: A comparison of results
highlighting the influence of the organic contents
F.-X Ouf, S. Bourrous, S. Fauvel, A. Kort, L. Lintis, J. Nuvoli, J. Yon
To cite this version:
F.-X Ouf, S. Bourrous, S. Fauvel, A. Kort, L. Lintis, et al.. True density of soot particles: A comparison
of results highlighting the influence of the organic contents. European Aerosol Conference (EAC 2019),
Aug 2019, Göteborg, Sweden. ￿hal-02275869￿
  
True density of soot particles: A comparison of results highlighting the influence of the 
organic contents 
F.-X. Ouf
1
, S. Bourrous
1
, S. Fauvel
1
, A. Kort
1, 2
 L. Lintis
1,3
, J. Nuvoli
1,3
 and J. Yon
4 
 
1
Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Gif-Sur-Yvette, 91192, France 
2
Ecole Nationale Supérieure des Mines, SPIN-EMSE, CNRS:UMR5307, LGF, 42023 Saint-Etienne, France 
3
Université de Lorraine, Laboratoire Réactions et Génie des Procédés (LRGP), UMR 7274, F-54000, Nancy, 
France. 
4
Normandie Université, INSA Rouen, UNIROUEN, CNRS, CORIA, 76000 Rouen, France. 
Keywords: soot, organic carbon, true density. 
 
True density is the density of the condensed material 
as opposed to the bulk density (density of a porous 
material or containing interparticles holes). For 
aggregates of primary spheres, as soot for example, 
true density refers to the density of the primary 
spheres. True density of powders has been widely 
measured since last century using Helium 
pycnometry
1
 and volume displacement methods such 
as ISO 787-23
2
. In most of the cases, within these 
methods, 500 mg of powder are at least needed to 
perform a relevant density analysis. This kind of 
analysis is suitable for industrial applications in the 
field of powder production, for which powder 
amount is not a limiting point. For research 
applications and specifically within the aerosol and 
soot scientific community, retrieving several hundred 
of milligrams of nanostructured carbonaceous 
particles from a burner, a diffusion flame or 
automotive / aircraft engines is a tremendous task. 
An alternative method, based on aerosol 
measurements (mainly based on DMA-CPMA 
analysis), has been recently proposed (Yon, Bescond, 
& Ouf, 2015). 
In the present study, a validation of ISO 787-23 and 
DMA-CPMA methods for measuring true density on 
reference black carbon samples is first proposed. 
Figure 1 presents the comparison between measured 
true density and reference true density for reference 
samples, highlighting the ability of both ISO 787-23 
and DMA-CPMA methods, for measuring this 
property for carbonaceous nanoparticles aggregates. 
 
Reference true density (kg/m3)
2000 3000 4000 50001000
M
e
a
s
u
re
d
 t
ru
e
 d
e
n
s
it
y
 (
k
g
/m
3
)
2000
3000
4000
5000
1000
Glass
Al2O3
Carbonaceous samples
LB 101
Printex 90
Glassy C.
Printex 25
DMA-CPMA approach
GFG1000
CAST 16.2% OC/TC
Measured = Ref.
Measured = +/- 5% . Ref.
 
Figure 1: validation of ISO 787-23 and DMA-CPMA 
methods of true density measurement 
                                                          
1
 https://www.astm.org/Standards/B923.htm  
2
 https://www.iso.org/standard/5102.html  
Furthermore, measurements of true density on 
samples representative of fire emissions at different 
scales are also presented and discussed, according to 
their respective experimental uncertainties. Figure 2 
presents the evolution of true density as a function of 
the organic carbon (OC) content, measured according 
to the Improve_A protocol (Chow et al., 2007) 
applied to the EC/OC analyzer from Sunset lab.  
 
OC/TC ratio (%)
0 20 40 60 80 100
S
o
o
t 
tr
u
e
 d
e
n
s
it
y
 (
k
g
/m
3
) 
1000
1200
1400
1600
1800
2000
2200
Soot containing
metals
 
Figure 2: Evolution of soot density as a function of 
OC/TC ratio (dashed line is a guide to the eye) 
 
An interesting correlation between the soot density 
and the OC content is observed and commented: the 
soot true density significantly decreases with their 
OC content increase. Three different ranges of 
densities are then proposed as a function of the 
OC/Total Carbon (TC) ratio of soot particles. For low 
OC content (i.e. less than 5%) and high OC content 
(i.e. more than 20%), respective mean values of  
1834 +/- 187 kg/m
3
 and 1285 +/- 217 kg/m
3 
are 
proposed. For intermediate OC content values, a 
fitting is applied according to a mixing law. Finally, a 
discussion is conducted on the relevance of using 
these values of soot true densities for temperature 
representative of those reported for industrial fires 
and ranging from 25°C to 240°C. 
 
 
Chow, J. C., Watson, J. G., Chen, L. W. A., Chang, 
M. C. O., Robinson, N. F., Trimble, D., & 
Kohl, S. (2007). J. Air & Waste Manag. Assoc. 
(1995), 57, 1014–1023.  
Yon, J., Bescond, A., & Ouf, F.-X. (2015). J. Aero. 
Sci., 87, 28–37.  


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True density of soot particles: A comparison of results highlighting the influence of the organic contents

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Archive Ouverte en Sciences de l'Information et de la Communication

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