Sb. Sun et Pr. Jaffe, SORPTION OF PHENANTHRONE FROM WATER ONTO ALUMINA-COATED WITH DIANIONIC SURFACTANTS, Environmental science & technology, 30(10), 1996, pp. 2906-2913
An aluminum oxide (alumina) coated with three dianionic surfactants (c
ommercial DOWFAX) was examined for its effectiveness to sorb phenanthr
ene from water, as a function of the surfactant loading rate and the s
urfactant alkyl chain length. The results showed that the dianionic su
rfactants adsorbed on alumina are effective phases for the sorption of
nonionic organic compounds (NOCs) such as phenanthrene, increasing th
e apparent distribution coefficient (K) of phenanthrene onto the soli
d phase by up to 3 orders of magnitude. The effectiveness of the surfa
ctants as sorptive phases was shown to increase with their carbon cont
ent(i.e., the alkyl chain length). To distinguish between the contribu
tions to the sorption of phenanthrene by surfactant monolayers and bil
ayers, the partitioning of phenanthrene onto the surfactant coated alu
mina was quantified over a large range of surfactant loading. Compared
on a unit surfactant mass basis, the bilayers of the dianionic surfac
tants are approximately 3-6 times as effective in terms of sorbing phe
nanthrene from water than the corresponding monolayers, showing that t
he organic carbon-normalized partition coefficient for these two sorbe
d surfactant phases differs. It was also shown that, on a per unit sur
factant mass basis, the partitioning of phenanthrene between the adsor
bed dianionic surfactant phases (monolayers and bilayers) and water is
5-7 (15 in one case) times more effective than that between the corre
sponding surfactants phases (monomers and micelles) in the aqueous pha
se and water.