Simultaneous electrokinetic removal of polycyclic aromatic hydrocarbons and metals from a sediment using mixed enhancing agents|
Ammami, M.T.; Benamar, A.; Wang, H.; Bailleul, C.; Legras, M.; Le Derf, F. & Portet-Koltalo, F.
The maintenance of harbor waterways generates
large amounts of dredged sediments which are
often rich in coexisting organic and inorganic contaminants.
Electrokinetic remediation treatments have
recently been developed for the simultaneous removal of
heavy metals and polycyclic aromatic hydrocarbons
(PAHs), using various enhancing agents generally tested
sequentially. In this study, different processing fluids
were tested, alone or mixed, to improve the decontamination
of aged model sediment contaminated with cadmium,
lead, chromium, copper, zinc, and five PAHs.
Nitric acid (NA) and citric acid (CA) were tested to
avoid the formation of an alkaline front into the sediment
and favor the metals removal, while an anionic
surfactant [sodium dodecyl sulfate (SDS)] and a nonionic
surfactant (Tween 20) were tested to solubilize and
mobilize PAHs. Processing fluids were circulated under a
constant voltage gradient of 1 V cm-1 for 10–14 days.
NA showed an excellent potential to remove metals
(76.8–99.9 % removal) and PAHs (70.3–89.7 % removal)
in a single run. Besides, the mixture of Tween 20 and
CA, more environmental friendly, could be considered as
a relatively good processing fluid for the simultaneous
removal of metals (10.3–90.8 % removal) and PAHs
(53.6–61.6 % removal) from the fine-grained sediment,
while SDS mixed to CA was not a good candidate for
this purpose (0.1–65 % removal for metals and
34.1–41.0 % removal for PAHs).
Electrokinetic remediation; Polluted sediments; Metals; Polycyclic aromatic hydrocarbon co-contaminants; Surfactants; Citric acid