Environmental Engineering Reference
In-Depth Information
8.
C
t
= 0
= initial contaminant concentration at
t
= 0 [mg l
−1
, M l
−1
];
9.
c
i
= concentration (mol dm
−3
; mol l
−1
) of the ith ion of charge,
z
i
.
10.
cp
= moles gaseous reactants-moles gaseous products;
11.
D
{A[ZVM]}
= diffusion coefficient =
k
B
T/ πβη r
s
;
12.
D
f
= Driving force, Pa (1 m head = 10,000 Pa);
13.
E
a
=Activation energy (kJ Mol
−1
);
14.
F
= Faraday constant;
15.
H
= Planck's constant;
16.
I
= ionic strength of the water = 0.5 Σ
c
i
Z
i
2
;
17. log (γ
A
) = −A'z
A
2
I
0.5
(lower ionic strengths);
18. log (γ
A)
= −A'z
A
2
I
0.5
/(1+B'a I
0.5
) (higher ionic strengths);
19. log (k
observed
/k
o
) = 1.018 z
A
z
B
I
0.5
;
20.
k
B
= Boltzmann's constant;
21.
k
o
= the rate coefficient at zero ionic strength =
k
r
K
AB
;
22.
k
observed
=observed contaminant removal rate constant [proportion removed
s
−1
]; k
observed
can also be expressed as mg
removed
s
−1
, or [moles removed mole reactant
−1
s
−1
], or another suitable set of units;
23.
k
p
= permeability,
m
3
m
−2
s
−1
Pa
−1
;
24.
k
sa
= reaction rate constant which has been normalized for ZVM surface area and ZVM concentration in the water;
25.
K
,
K
AB
= Equilibrium constant;
26.
K
p
= equilibrium constant adjusted for pressure;
27.
K
ǂ
(γ
A
γ
ZVM
/γ
{A[ZVM]}
) = exp(−ΔG
ǂ
/RT) and RT(Ln (K
ǂ
(γ
A
γ
ZVM
/γ
{A[ZVM]}
)) = −ΔG
ǂ
;
28.
n
= number of electrons transferred;
29.
P
= pressure;
30.
P
p
= reactant partial pressure;
31.
p
m
= mass concentration of ZVM at
t
(g l
−1
).
p
m
decreases as ZVM ions are removed with the product water and as ZVM
is replaced with ZVM-hydroxides, peroxides, oxides, carbonates, sulphates, sulphides, etc.;
32.
Q
= reaction quotient;
33.
Q
fr
= flow rate, m
3
hr;
34.
R
= gas constant;
35.
r
{A[ZVM]}
= encounter radius (nm) of the reactant [A]: ZVM interaction;
36.
r
s
= hydrodynamic radius (nm) of the diffusing species;
37. SV = space velocity,
m
3
hr
−1
t
−1
ZVM;
38. SWZ = stored water to ZVM ratio in the reaction environment,
m
3
H
2
O
t
−1
ZVM;
39.
S
w
=Volume of water contained in the reaction environment,
m
3
;
40. T = Temperature, K;
41.
t
(time) can be expressed in seconds, minutes, hours, days;
42.
W
zvm
= weight (
t
) of ZVM in the reaction environment;
43.
Xm
= number of moles of the gaseous reactant;
44. z
A
= charge number of ion species;
45. z
B
= charge number of ion species, B;
46. ZVM = zero valent metal;
47. Η = viscosity;
48. Β = a constant (continuum solvent, β = 6; molecular diffusion, β = 4);
49. K = transmission coefficient (e.g., 1.0);
50. ΔE
o
= standard potential for the reaction; ΔE = Eh;
51. ΔG
ǂ
= overall Gibbs free energy of activation = ΔG
o
{A[ZVM]}
+ ΔG
*
;
52. ΔG
o
= standard Gibbs free energy for a reaction;
