Surfactant-Enhanced Solubilization and Simultaneous Degradation of Phenanthrene in Marine Sediment by Electro-Fenton Treatment

Polycyclic aromatic hydrocarbons (PAHs) are one of the main types of contaminants entering the coastal marine environment. Therefore, when polluted sediments are dredged, they should be remediated for beneficial use. Numerous methodologies can be applied to remove these hydrophobic substances from solid matrixes. Among them, the use of surfactants shows a potential application on solubilizing organic pollutants. In this work, critical micelle concentration (cmc) studies of synthetic nonionic surfactants such as Brij 35, Tween 80, Triton X-100, and the biosurfactant Saponin were realized. Furthermore, the impact of several parameters such as pH and ionic strength was assayed. Mixed surfactant systems, synthetic and Saponin, were evaluated, obtaining that, for phenanthrene solubilization, the best results were reached with the mixture Saponin:Tween 80 (1:1.2 mmol L-1). Finally, the electro-Fenton treatment of sediment polluted with phenanthrene was carried out, attaining near complete phenanthrene removal after 1 day when the optimized surfactant mixture was used.