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 Fe 3 O 4 -SiO 2 -Dimethoxydiphenylsilane (Fe 3 O 4 -SiO 2 -2DMDPS) nanocomposite was fabricated from encapsulation and grafting process. Magnetic Fe 3 O 4 nanoparticles were served as preliminary matrix material , SiO 2 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 π-π interaction. SEM-EDS, TEM , BET, VSM, XRD, FTIR, Raman, Zeta potential , and XPS techniques were used to characterize magnetic nanocomposite. The prepared Fe 3 O 4 -SiO 2 -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 Fe 3 O 4 -SiO 2 -2DMDPS and PHE molecules, confirmed the π-π interaction was valid and it usually existed in the form of parallel-displaced. This work might aid us to develop effective modification strategy for Fe 3 O 4 nanoparticles and expand its application in the PAHs removing field.