Environmental Engineering Reference
In-Depth Information
Table 2
(continued)
Surfactant
Chemical structure
cmc
a
AN
b
T (°C) Reference
Igepal CA-720
(4-C
9
H
19
)C
6
H
4
O(CH
2
CH
2
O)
12
H
169
Edwards et al.
(1991)
Igepal CO-730
(4-C
9
H
19
)C
6
H
4
O(CH
2
CH
2
O)
15
H
246
52-80
25
Fendler and
Fendler
(1975)
Tergitol NP-10
(4-C
9
H
19
)C
6
H
4
O(CH
2
CH
2
O)
10.5
H 36.9
Edwards et al.
(1991)
Brij-30
C
12
H
25
O(CH
2
CH
2
O)
4
H
8.3
Krogh et al.
(2003)
Brij-35
C
12
H
25
O(CH
2
CH
2
O)
23
H
74
Kile and Chiou
(1989)
Neodol 91-6
C
9-11
H
19-23
O(Ch
2
CH
2
CH
2
O)
6
H
250
242
Heredia and
Bukovac
(1992)
Neodol 91-20
C
9-11
H
19-23
O(CH
2
CH
2
O)
20
H
390
64
Silwet L-77
n = 7-8
d
600
Locke et al.
(2002)
Miscellaneous
Monorhamnolipid
R = (CH
2
)
6
CH
3
e
54
Mata-Sandoval
et al. (2000)
DDAPS
C
12
H
25
(CH
3
)
2
N
+
(CH
2
)
3
SO
3
−
402
25
Fendler and
Fendler
(1975)
a
Critical micelle concentration in mg/L.
b
Aggregation number.
c
Nonionic surfactant (b) in Fig. 2.
d
Nonionic surfactant (e) in Fig. 2.
e
Miscellaneous surfacatant (b) in Fig. 2.
(b)
[Substrate]
(a)
Surface tension
cmc
cmc
[Surfactant]
[Surfactant]
Fig. 4
Effect of surfactant on (a) apparent solubility of a substrate and (b) surface tension of solu-
tion.
cmc
, critical micelle concentration
In the simplified model of a spherical micelle, the core region made of alkyl
chains is considered to be hydrophobic and fluid and can solubilize an apolar sub-
strate (Bunton et al. 1991; Ta¸cio ˘lu 1996). As shown in Fig. 3, the outer region of
the micelle consists of polar head groups known as a Stern layer where a part of the
counterions are tightly bound in the case of ionic surfactants and the polarity is
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