particles at 1.6 Â 10
4
mg/m
3 in a thermophoresis
cell. Based on these studies, it can be concluded
that thermophoresis is an effective strategy for
capturing nanoscale particles [87, 88].
Particle Coagulation
Particles in an aerosol collide due to their differing
relative velocities, due to thermal Brownian
motion, electro- or thermophoresis, momenta,
and so on. Most of the time, colliding particles
form an aggregate that coalesces; the process of
coagulation changes the size distribution but not
the mass density. From the perspective of nanoparticle control, coagulation is a mechanism that
could be used to shift material into a size range
that is easier to control with standard technologies. Katoshevski et al. have described using
coagulation for nanoparticle control [89]. The
attractive interaction mechanisms between particles such as electrostatic, Van der Waals, and
Airborne Nanoparticles: Control and Detection,
Fig. 17 Grade efficiency vs. particle diameter (a) for a
gas velocity of 3.3 cm/s at different KCl AQCs of 0.2, 0.4,
and 2 g/L with related GACs of 7.26, 15.55, and 45.78 mg/
m
3
, respectively, and (b) for gas velocities of 6.6, 8.2, and
9.9 cm/s, with KCl AQCs of 4.0, 5.0, and 6.0 g/l, respectively. (Reprinted with permission [79])
Airborne Nanoparticles: Control and Detection, Table 7 The collection performance of ESPs
Process
Operation
mode
Operation
stage
Particles
size/nm
Air
velocity/
cm/s
Applied voltage/kV
Collection
efficiency/%
Study
ESP
Wire-totube
Single,
two
50–500
0.35
0.7
À7.5 to À10
>90
>70
[72]
ESP
Electrospray
+ESP
Wire-toplate
Single
100–300
90–260
800
800
À19.1
EHA(À4 kV/cm)/
ESP(À16.2 kV)
95-(~100)
70–80
[73]
WESP
Wire-toplate
Single
20–80
80–600
–
+4.2
40–70
70–90
[74]
ESP-fine
water
ESP + fine
water
Wire-toplate
Single
30–8100
62–500
À15 to À34
67.9–92.9
99.2–99.7
[75]
ESP
Wire-onplate
Single
30–1870
0.25
0.5
À18
98.8–99.9
90.9–99.7
[78]
ESP
Wire-toplate
Single
10/250
3.3
À8
~100/~90
[79]
ESP
Wire-toplate
Single
10–30
30–224
1.7–6.6
4 kV/cm
90–100
~100
[80]
112
Airborne Nanoparticles: Control and Detection
4
mg/m
3 in a thermophoresis
cell. Based on these studies, it can be concluded
that thermophoresis is an effective strategy for
capturing nanoscale particles [87, 88].
Particle Coagulation
Particles in an aerosol collide due to their differing
relative velocities, due to thermal Brownian
motion, electro- or thermophoresis, momenta,
and so on. Most of the time, colliding particles
form an aggregate that coalesces; the process of
coagulation changes the size distribution but not
the mass density. From the perspective of nanoparticle control, coagulation is a mechanism that
could be used to shift material into a size range
that is easier to control with standard technologies. Katoshevski et al. have described using
coagulation for nanoparticle control [89]. The
attractive interaction mechanisms between particles such as electrostatic, Van der Waals, and
Airborne Nanoparticles: Control and Detection,
Fig. 17 Grade efficiency vs. particle diameter (a) for a
gas velocity of 3.3 cm/s at different KCl AQCs of 0.2, 0.4,
and 2 g/L with related GACs of 7.26, 15.55, and 45.78 mg/
m
3
, respectively, and (b) for gas velocities of 6.6, 8.2, and
9.9 cm/s, with KCl AQCs of 4.0, 5.0, and 6.0 g/l, respectively. (Reprinted with permission [79])
Airborne Nanoparticles: Control and Detection, Table 7 The collection performance of ESPs
Process
Operation
mode
Operation
stage
Particles
size/nm
Air
velocity/
cm/s
Applied voltage/kV
Collection
efficiency/%
Study
ESP
Wire-totube
Single,
two
50–500
0.35
0.7
À7.5 to À10
>90
>70
[72]
ESP
Electrospray
+ESP
Wire-toplate
Single
100–300
90–260
800
800
À19.1
EHA(À4 kV/cm)/
ESP(À16.2 kV)
95-(~100)
70–80
[73]
WESP
Wire-toplate
Single
20–80
80–600
–
+4.2
40–70
70–90
[74]
ESP-fine
water
ESP + fine
water
Wire-toplate
Single
30–8100
62–500
À15 to À34
67.9–92.9
99.2–99.7
[75]
ESP
Wire-onplate
Single
30–1870
0.25
0.5
À18
98.8–99.9
90.9–99.7
[78]
ESP
Wire-toplate
Single
10/250
3.3
À8
~100/~90
[79]
ESP
Wire-toplate
Single
10–30
30–224
1.7–6.6
4 kV/cm
90–100
~100
[80]
112
Airborne Nanoparticles: Control and Detection