NiFe₂O₄-based magnetic covalent organic framework nanocomposites for the efficient adsorption of brominated flame...

A new kind of NiFe₂O₄-based magnetic covalent organic framework nanocomposites (NiFe₂O₄@COFs) was fabricated through facile synthesis approach under room temperature. The NiFe₂O₄@COFs exhibited higher adsorption capacity for brominated flame retardants than carbon nanotube material based on hydrophobic interactions, π-π stacking interaction, and van der Waals forces. In addition, the adsorption isotherm and the kinetic model were more suitable for Langmuir and pseudo-second-order model, respectively. NiFe₂O₄-based magnetic covalent organic framework nanocomposites combined with HPLC-UV (absorption wavelength: 214 nm) technology has excellent adsorption performance, which exhibited low detection limits (0.03-1.9 μg L^-1), wide linear range (0.11-1000 μg L^-1), good recoveries (91.5-102%) with a relative standard deviation of less than 2.9%. Finally, the prepared magnetic material was successfully used asadsorbents of magnetic solid-phase extraction and applied to the determination of five BFRs from the real water samples. The adsorption and removal of BFRs by NiFe₂O₄@COFs from water samples.