Environmental Engineering Reference
In-Depth Information
Surface concentration balance:
c s
3
R
(1
α
)
t =
k p ( c
c s )
kc s −→
first-order reaction.
α
Initial conditions:
c ( t
=
0
,
z )
=
0
=
,
=
.
c s ( t
0
z )
0
Boundary conditions:
c ( t
0
,
z
=
0)
=
c 0 ( t )
c s ( t
0
,
z
=
0)
=
0
c ( t
,
z
→∞
)
=
finite
.
Laplace transform:
2 c
D 0
α
v
c
3
R
(1
α
)
3
R
(1
α
)
z
s c
k p ( c
c s )
s c
+
k p ( c
c s )
k c s =
0
,
z 2
α
α
yielding:
k p s
k p
(1
α
)
(1
α
)
3
R
3
R
c s =
+
+
k
α
α
v 0
α .
v =
D c v
c
A c
=
0
,
3
R
k p
+
(1
α
)
3
R
(1
α
)
α
from
c
s
k p
where A
=
k p
1
s
term
.
3
R
(1
α
)
α
t
+
k
+
α
Boundary conditions:
c ( z
=
0)
=
c 0 ( s )
→∞
=
.
c ( z
)
finite
Solution to part (b)
4 D 0 A
1
2 D 0
c 0 e λ z
2
c ( z )
=
where
λ =
v 0 ±
v
0 +
(lim s 0 e λ z )
m 0 ( z )
=
lim s 0 c ( z )
=
( lim s 0 c 0 )
m 0 ( z
=
0)
4 D 0 lim s 0 A
1
2 D 0
0
lim s 0 λ =
v 0
v
+
λ 0
0
k p 3
R
(1
α
)
3
R
(1
α
)
.
α
lim s 0 A
=
k p
1
3
R
(1
α
)
α
k
+
k p
α
0)e λ z
m 0 ( z )
=
m 0 ( z
=
.
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