Electronic Supplementary Material (ESI) for Physical Chemistry Chemical Physics.
This journal is © the Owner Societies 2015
Influence of relative humidity on heterogeneous kinetics of
NO2 on kaolin and hematite
Yongchun Liu, Chong Han, Jinzhu Ma, Xiaolei Bao, Hong He
State Key Joint Laboratory of Environment Simulation and Pollution Control,
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences,
Beijing, 100085, China.
Supporting information
Figure S1. Diagram of the flow tube
Corresponding author phone: +86-10-62849123;
fax: +86-10-62923563; email: [email protected]

cNO(ppbv)
cNO(ppbv)
10
8
6
4
2
0
10
8
6
4
2
0
279.9 mg Kaolin
247 mg Hematite
(A) RH 47%
-20 -10 0
(B) RH 7%
10
-20
10 20 30
Time (min)
-10
0
20
30
40 50 60
261.5 mg Kaolin
262.9 mg Hematite
40
50
60
Figure S2. Evolution of NO concentrations with time during uptake of NO2 on kaolin
and hematite at RH of (A) 47 % and (B) 7 %. At other relative humidities, the signal
responses of NO on both kaolin and hematite were similar to those shown in (A).
1.5x10-7
Experiment data
H-L model fitting curve
(A) Kaolin
1.0x10-7
10s
5.0x10-8
0.0
(B) Hematite
1.5x10-6
1.0x10-6
5.0x10-7
0.0
0
10
20
30
40
50
RH (%)
60
70
80
Figure S3. Modelling result assuming a Langmuir adsorption isotherm of water vapor
and Langmuir-Hinshelwood reaction mechanism of NO2 on the particles.
1.2
1.0
1.0
0.8
0.8
0.6
0.6
c/c0
c/c0
(B) -Fe2O3
(A) kaoline
1.2
RH 47 %
298 K
0.4
0.2
0.0
353.4 mg with Na2CO3 denuder
400.8 mg without Na2CO3 denuder
RH 47 %
298 K
247 mg with Na2CO3 denuder
239.5 mg without Na2CO3 denuder
0.4
0.2
0.0
-10 0 10 20 30 40 50-10 0 10 20 30 40 50
Time (min)
Time (min)
Figure S4. Comparison of the uptake curves of NO2 with or without Na2CO3 denuder
at 298 K and at 47 % of RH. The time resolution is 1 min.
Relative ratio of NO2 removed by Na2CO3
denuder to initial NO2 concentration (%)
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
10
20 30 40 50 60
Relative humidity (%)
70
80
Figure S5. The relative ratio of NO2 removed by Na2CO3 denuder to the initial NO2
concentration at different RH.
6.0x10-8
RH 0%
Uptake capacity (mol)
Kaolin
4.0x10-8
-8
3.0x10
RH 32%
5.0x10-8
RH 47%
4.0x10-8
RH 74%
4.0x10-8
3.0x10-8
4.0x10-8
3.0x10-8
-8
3.0x10
2.0x10-8
2.0x10-8
-8
2.0x10-8
2.0x10
1.0x10-8
1.0x10-8
-8
2.0x10
1.0x10-8
1.0x10-8
0.0
Na2CO3 denuder
Without Na2CO3
6.0x10-8
-8
4.0x10
ematite
0.0
0.0
0.0
0 100 200 300 400
Uptake capacity (mol)
RH 15%
0 100 200 300 400
0 100 200 300 400
5.0x10-8
-8
4.0x10
2.0x10-8
-8
1.0x10
0.0
2.0x10-8
2.0x10-8
-8
1.0x10
1.0x10-8
0.0
0
100 200 300
Sample mass (mg)
3.0x10-8
200
400
2.0x10-8
-8
2.0x10
0
3.0x10-8
3.0x10-8
-8
3.0x10
0.0
0 200 400 600 800
0.0
0.0
0 100 200 300 400
Sample mass (mg)
-8
1.0x10
0 100 200 300 400
Sample mass (mg)
0.0
0 100 200 300 400
Sample mass (mg)
0 100 200 300 400
Sample mass (mg)
Figure S6. Linear mass dependence for integrated uptake capacity of NO2 within 30
min on kaolin and hematite at 298 K. The first row is for kaolin and the second row is
for hematite.