Environmental Engineering Reference
In-Depth Information
Table 8.1
Properties of macroporous resins [6]. Reproduced with kind permission of Kluwer
Academic Publishers.
Bulk density,
Wet-
ρ
b
,
wet
% Swelling
exchange
Max
(drained),
due to
pH
capacity,
flowrate,
Max
T
,
◦
C
Resin
kg
/
L
exchange
range
eq
/
L
/
h
Regenerant
Polystyrene-
HCl,
H
2
SO
4
,
sulfonic acid
4% DVB
0.75-0.85
10-12
120-150
0-14
1.2-1.6
30
or NaCl
8-10% DVB
0.77-0.87
6-8
0-14
1.5-1.9
30
Polyacrylic
0.70-0.75
20-80
120
4-14
3.3-4.0
20
110% of
acid (gel)
theory HCl,
H
2
SO
4
Polystyrene-
0-7
∼
20
60-80
0-14
1.3-1.5
17
NaOH
quaternary
ammonium
Polystyrene-
0.67
8-12
100
0-7
1.8
17
NaOH
tert-amine
(gel)
CH
2
CH
SO
3
Figure 8.2
Strong-acid ion-exchange monomer (benzene-sulfonic acid) [6].
Reproduced with kind permission of Kluwer Academic Publishers.
two steps (
R
−
represents the negatively charged functional group of the resin), the second
of which is the regeneration step. The hydrogen cycle can be regenerated with HCl or with
H
2
SO
4
, and the sodium cycle can be regenerated with NaCl [4].
CaSO
4
+
2(
R
−
H
+
)
(2
R
−
)Ca
2
+
+
→
H
2
SO
4
Hydrogen cycle:
(2
R
−
)Ca
2
+
+
2(
R
−
H
+
)
H
2
SO
4
→
CaSO
4
+
CaSO
4
+
2(
R
−
Na
+
)
(2
R
−
)Ca
2
+
+
→
Na
2
SO
4
Sodium cycle:
(2
R
−
)Ca
2
+
+
2(
R
−
Na
+
)
2NaCl
→
+
CaCl
2
.
Strong-acid exchangers can also convert neutral salts into their corresponding acids if
operated in the hydrogen cycle which is a process known as salt splitting (weak-acid
resins cannot do this) [4].
Search WWH ::
Custom Search