Environmental Engineering Reference
In-Depth Information
Cationic surfactants
(a) Alkyltrimethylammonium halide (b) Alkylpyridinium halide
CH
3
X
H
3
C
N
(CH
2
)nCH
3
N
(CH
2
)nCH
3
CH
3
X
Anionic surfactants
(a) Sodium alkylsulfate (b) Sodium alkylsulfonate (c) Sodium alkylpolyethoxysulfate
C
m
H
2m+1
(OCH
2
CH
2
)
n
OSO
3
Na
C
n
H
2n+1
OSO
3
C
n
H
2n+1
SO
3
Na
Na
(d) Sodium alkylbenzenesulfonate
C
n
H
2n+1
SO
3
Na
Nonionic surfactants
(a) Alcohol ethoxylate
(b) Octylphenoxy ethoxylate
CH
3
CH
3
CH
3
(CH
2
)
m
O(CH
2
CH
2
O)
n
H
H
3
C
C
CH
2
C
O(CH
2
CH
2
O)
n
H
CH
3
CH
3
(c) Alkylphenoxy ethoxylate (d) Sorbitan alkylate
H(OCH
2
CH
2
)
w
O
O(CH
2
CH
2
O)
x
H
CH
3
(CH
2
)
m
O(CH
2
CH
2
O)
n
H
O(CH
2
CH
2
O)
y
H
CH
O
(e) Silicone derivative
CH
2
O(CH
2
CH
2
O)
z
C(=O)R
OSi(CH
3
)
3
H
3
C
Si
(CH
2
)
3
(OCH
2
CH
2
)
n
OCH
3
OSi(CH
3
)
3
Miscellaneous
(a) Zwitterionic surfactant (b) Biosurfactant (Monorhamnolipid)
O
H
C
H
2
H
C
R
H
C
CH
3
2
OH
O
O
O
(CH
2
)
6
CH
3
C
C
COOH
CH
3
(CH
2
)
11
N
(CH
2
)
3
SO
3
H
3
C
CH
3
OH
OH
Fig. 2
Chemical structures of typical surfactants
alkylbenzene. Recently, silicone derivatives such as Silwet L-77 showing a higher
surface activity have been developed for formulations (Stevens 1993). As other
categories, a zwitterionic surfactant having both cationic and anionic parts in a
molecule and many kinds of biosurfactants including rhamnolipids produced by
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