Environmental Engineering Reference
In-Depth Information
Enriched Ca(NO
3
)
2
can be recycled and sold as by-product.
Combined with lime, nitrates can be used as construction materials.
This technology can also co-produce the ammonia sulfate fertilizer by using
the FGD system that re-utilizes ammonia. In addition, solutions such as
NaS/NaOH can also be used to absorb the pollutants.
Ozone oxidation mechanisms are explained possibly as below. Analytically,
both the oxidation of SO
2
and CO seem not as quick as the NO
x
reaction.
O
3
+NO=NO
2
+O
2
(2.1)
O
3
+2NO
2
=N
2
O
5
+O
2
(2.2)
CO+O
3
=CO
2
+O
2
(2.3)
SO
2
+O
3
=SO
3
+O
2
(2.4)
O
3
+Hg=HgO+O
2
(2.5)
2.2 Ozone Characteristics
In general, each ozone molecule with the potential molecular structures presented
in Fig. 2.2, comprises three oxygen atoms. Ozone is chemically active and has a
pungent odor. 85% 90% of the total available natural ozone is located in the
stratosphere. The 10 45 km space surrounding the Earth is occupied by ozone
and thus called the ozonesphere. Ozone in the stratosphere protects the Earth by
absorbing the ultraviolet radiation. However, harmful ozone can be produced
through the photochemical reactions of VOCs and NO
x
with sunshine
[4]
.
O
O
O
O
O
O
O
O
O
O
O
O
(a)
(b)
(c)
(d)
Fig. 2.2
Typical structures of the ozone resonance hybrid molecule
As a blue gas with density of 2.144 kg/m
3
at standard state, ozone melts at
192.5 °C and boils at 111.9 °C. At standard state, its water solubility is 13 times
higher than that of oxygen and 25 times higher than that of air. Ozone
automatically decomposes into oxygen so that it is not stable enough in the air.
Again, ozone is explosive when its concentration exceeds 25% because of the
massive heat produced from decomposition. Fortunately, its concentration in air is
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