Cosolubilization of phenanthrene and pyrene in surfactant micelles: Experimental and atomistic simulations studies

Abstract

Solubilization of mixed phenanthrene (PHE) and pyrene (PYR) in Triton X-100 (TX), sodium dodecyl sulfate (SDS) and mixed TX-SDS surfactant solutions were done to observe their cosolubilization effect. Moreover, molecular dynamics (MD) simulations were performed to reveal how polycyclic aromatic hydrocarbons (PAHs) coexist in the micelle. Cosolubilization of PHE and PYR exhibited synergism along with decreasing synergistic extent with increasing SDS in mixed micelle. MD simulations verified the distribution of PHE and PYR in the shell and core regions of pure SDS and mixed SDS-TX micelles (with molar ratio of 1: 1), which were chosen as the representative systems for simulation study. The movement of PHE and PYR inside the micelle along with their different probability to contact with SDS non‑hydrogen atoms in pure SDS and mixed SDS-TX solubilization systems suggests the different solubilization sites of the two PAHs inside the micelle leading to their coexistence in the micelle. This study implies the significance of considering cosolubilization effects between PAH mixtures in determining surfactant concentration for environmental remediation.