High-efficiency adsorption of phenanthrene by Fe₃O₄-SiO₂-dimethoxydiphenylsilane nanocomposite: Experimental and theoretical study

Phenanthrene (PHE), as one of representative polycyclic aromatic hydrocarbons (PAHs) can cause serious adverse effects on human health, developing effective adsorbents to alleviate PHE contamination is in urgent demand. A novel Fe3O4-SiO2-Dimethoxydiphenylsilane (Fe3O4-SiO2-2DMDPS) nanocomposite was fabricated from encapsulation and grafting process. Magnetic Fe3O4 nanoparticles were served as preliminary matrix material, SiO2 was used to link the magnetic oxide and provide hydroxyl groups for proceeding the silane coupling reaction subsequently, and the aromatic rings in DMDPS could provide active sites for PHE adsorption via pi-pi interaction. SEM-EDS, TEM, BET, VSM, XRD, FTIR, Raman, Zeta potential, and XPS techniques were used to characterize magnetic nanocomposite. The prepared Fe3O4-SiO2-2DMDPS exhibited an excellent adsorption performance towards PHE, it could maintain 75.97% adsorption capacity after four regeneration cycles. Homogeneous adsorption acted crucial role in the whole adsorption process and film diffusion was the rate controlling procedure. Theoretical calculations put forward the most favorable bonding modes between Fe3O4-SiO2-2DMDPS and PHE molecules, confirmed the pi-pi interaction was valid and it usually existed in the form of parallel-displaced. This work might aid us to develop effective modification strategy for Fe3O4 nano particles and expand its application in the PAHs removing field.