posted on 2023-04-11, 11:33authored byXiaohan Meng, Ze Lv, Liyin Shi, Tianzhen Jiang, Shaoyang Sun, Yan Li, Jianguo Feng
Residues of pyrethroid pesticides in aquatic environments
seriously
threaten aquatic organisms and the human health. Herein, a novel highly
dispersed and recyclable composite ZIF-8 and SiO2 double-layer-modified
Fe3O4 nanoparticle, named Fe3O4@ZIF-8@SiO2 nanoparticle, was synthesized via a
layer-by-layer assembly method to remove pyrethroid insecticides (namely,
fenvalerate, β-cyfluthrin, and tetramethrin) from water. The
physical properties of the Fe3O4@ZIF-8@SiO2 nanoparticles were characterized via scanning electron microscopy,
elemental mapping, energy-dispersive X-ray spectroscopy, X-ray diffraction,
Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy,
inductively coupled plasma spectroscopy, thermogravimetric analysis,
Brunauer–Emmett–Teller surface area analysis, dispersion
analysis, and vibrating sample magnetometry. The prepared Fe3O4@ZIF-8@SiO2 nanoparticles exhibited excellent
adsorption performance and high dispersibility and could be rapidly
separated from water using an external magnetic field. The Fe3O4@ZIF-8@SiO2 nanoparticles exhibited
the strongest adsorption effect at an adsorbent dosage of 10 mg, an
adsorption time of 40 min, and a pH of 7. The fitted model for the
adsorption process was consistent with the proposed secondary kinetic
model and Sips isotherm model. The Fe3O4@ZIF-8@SiO2 nanoparticles exhibited maximum adsorption capacities of
316.23, 364.43, and 258.69 mg g–1 for fenvalerate,
β-cyfluthrin, and tetramethrin, respectively. The Fe3O4@ZIF-8@SiO2 nanoparticles retained most of
their adsorption capacity after five reuse cycles when acetone was
used as an eluent for desorption. The mechanisms involved in the adsorption
process included π–π stacking interactions, hydrogen
bonds, hydrophobic interactions, and pore filling effects. This study
provides a potential design for rapidly recoverable and reusable nanoparticles
that can be used to effectively adsorb pyrethroid insecticides in
wastewater.