Magnetic Permanently Confined Micelle Arrays for Treating Hydrophobic Organic Compound Contamination

Abstract

Magnetic permanently confined micelle arrays (Mag-PCMAs) have been successfully synthesized as sorbents for hydrophobic organic compound (HOC) removal from contaminated media. The synthesis of Mag-PCMAs involves coating a silica/surfactant mesostructured hybrid layer on the negatively charged Fe₃O₄ microparticles to create a core/shell structure. The surfactant, 3-(trimethoxysily)propyl-octadecyldimethyl-ammonium chloride (TPODAC), has a reactive endgroup -Si(OCH₃)₃ on its hydrophilic groups, which allows the surfactant micelles to permanently anchor on the silica framework through covalent bonding. This unique structural property avoids surfactant loss during application and allows for sorbent regeneration. The isotherms and kinetics of four representative HOCs (atrazine, diuron, naphthalene, and biphenyl) onto Mag-PCMAs were determined, and the regeneration and reusability of Mag-PCMAs for diuron removal was also investigated. As a proof of principle for application of Mag-PCMAs for soil-washing, the use of Mag-PCMAs for removal of diuron from a contaminated soil was also demonstrated. All of the results showed that Mag-PCMAs are reusable sorbents for fast, convenient, and highly efficient removal of HOCs from contaminated media.