Co-solubilization of polycyclic aromatic hydrocarbon mixtures in aqueous micellar systems and its correlation with FRET for enhanced remediation processes.

Surfactant enhanced remediation (SER) is an effective approach for decontaminating the PAH polluted soils. Solubilization and Cosolubilization of Phenanthrene (Ph), Pyrene (Py) and Perylene (Pe) as single, binary and ternary mixtures have been studied employing cationic (CTAB), anionic (SDS), non-ionic surfactant (Brij 30) and block copolymer (P123) micelles. In the single solute solubilization studies, solubility of Pe follows the order Brij 30 > CTAB > SDS whereas Ph or Py followed the order of CTAB > Brij 30 > SDS. In the cosolubilization studies, an increase, decrease or no change in the mutual solubility of PAHs was observed. Synergism in solubilization was observed most in P123 in both binary and ternary PAH mixture where more PAHs could get solubilized in the dense micellar shell region, thereby enhancing the micellar core volume leading to enhanced solubilization of PAHs. The solubilizates as pairs (Ph-Pe and Py-Pe) were further tested for any possible energy transfer in presence of surfactant based restricted host environments using spectrofluorometry and spectrophotometry. Based on the solubilization and cosolubilization an efficient non-radiative energy transfer (FRET) was observed between Ph/Py (donor) and Pe (acceptor) in the non-ionic surfactant system as well as in CTAB-Brij 58 mixed system. The results of this work may improve the effective utilization of surfactants in their correct evaluation for the removal of PAHs from contaminated soils or aquifers treated with SER technology.