Large admicelles on superparamagnetic polystyrene nanoparticles as a novel adsorbent

In our previous study, cetyltrimethylammonium bromide (CTAB) admicelles on polystyrene (PS) microspheres for the adsolubilization of phenanthrene had been developed. In this work, CTAB admicelles modified on magnetic PS nanocomposites was used as a novel adsorbent to facilitate magnetic separation. Magnetic PS (MPS) nanoparticles (NPs) were synthesized by miniemulsion polymerization, in which the emulsifier was polyvinylpyrrolidone (PVP) and an oil phase consisted of oleate-modified Fe3O4 NPs dispersed in octane and styrene as the monomer. MPS NPs and CTAB-modified MPS NPs were characterized using transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), Brunauer–Emmet–Teller, and atomic force microscopy (AFM) analysis. The TEM results revealed that the MPS NPs had regularly spherical shape with an average diameter of 140 nm. The saturation magnetization (Ms) of MPS NPs and CTAB-modified MPS NPs were 49.04 and 32.52 emu·g−1, respectively. Unexpectedly, AFM images revealed that the large admicelles were formed on MPS NPs due to PVP, and the height of the aggregates was 64 nm, 5.3 times as much as that of the aggregates on the PS microsphere. For CTAB-modified MPS NPs, the height of the aggregates increased to 99.9 nm. Through CTAB modification, the specific surface area of the MPS NPs notably reduced from 2.36 to 1.06 m2 g−1, which indirectly verified that bigger CTAB admicelles were formed. Cation–π electron interaction enabled phenanthrene to be adsolubilized in CTAB admicelles on MPS NPs. The equilibrium adsorption capacity of the CTAB-modified MPS NPs for phenanthrene was 24.3 mg g−1, which was 1.7, 2.1, and 6.0 times higher than the amount of the MPS NPs, CTAB-modified and original PS microspheres, respectively. The surface of magnetic polystyrene nanoparticles CTAB admicelles on the surface of MPS NPsMagnetic PS (MPS) nanoparticles (NPs) were synthesized by miniemulsion polymerization, where polyvinylpyrrolidone (PVP) as an emulsifier, styrene and oleate modified Fe3O4 nanoparticles (NPs) dispersed in octane as an oil phase. MPS NPs were spherical and the average size was 140 nm. The Fe3O4 NPs diffused in PS nanospheres, rather than core-shell structure. They were more prone to moving the surface of the nanosphere.The large admicelles were formed on MPS NPs as a result of PVP, the height of the aggregates was 64 nm. On CTAB modified MPS NPs, the height of the aggregates increased to 99.9 nm.Cation–π electron interaction helped phena