Environmental Engineering Reference
In-Depth Information
TABLE 14.4
Common Oxidation States for Nitrogen
Increasing Levels of Sulfur Oxidation
Oxidation State of N
Form
−3
0
+1
+2
+3
+4
+5
Aqueous solution and
salts
NH
+
NO
−
NO
3
−
NH
3
Gas phase
NH
3
N
2
N
2
O
NO
NO
2
14.5.1.4 Ammonia Speciation
Ammonia in water may occur in one of two forms, depending on the pH and temperature. The ion-
ization reaction maybe written as (USEPA 1999b)
+
+
NH NH
+
H
(14.15)
4
3
We t and dry deposition
Gas-film
controlled
volatilization
Liquid-film
controlled
volatilization
O
2,s
N
2,s
Air
Water
O
2
Denitrification
NH
3
High
pH
N
2
O
NO
Anammox
Low
pH
Ammonification
Nitrification
Nitrification
NH
+
Organic N
NO
-
N
2
NO
-
denitrification
Net production
Nitrogen fixation
Settling
Sediment release
FIGURE 14.22
Nitrogen processes.
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