Fe3O4@SiO2 magnetic nanocomposites as adsorbents for removal of diazinon from aqueous solution: isotherm and kinetic study

Abstract

PurposeThe purpose of this study was to the synthesis of Fe3O4@SiO2 nanocomposites and using it as an adsorbent for removal of diazinon from aqueous solutions. Structural characteristics of the synthesized magnetic nanocomposite were described by Fourier transform infrared spectroscopy and scanning electron microscopy.Design/methodology/approachThe effects of different parameters including pH (2-10), contact time (1-180 min), adsorbent dosage (100-2000 mg L−1) and initial diazinon concentration (0.5–20 mg L−1) on the removal processes were studied. Finally, isotherm and kinetic and of adsorption process of diazinon onto Fe3O4@SiO2 nanocomposites were investigated.FindingsThe maximum removal efficiency of diazinon (96%) was found at 180 min with 1000 mg L−1 adsorbent dosage using 0.5 mg L−1 diazinon concentration at pH = 7. The experimental results revealed that data were best fit with the pseudo-second-order kinetic model (R2 = 0.971) and the adsorption capacity was 10.90 mg g−1. The adsorption isotherm was accordant to Langmuir isotherm.Originality/valueIn the present study, the magnetic nanocomposites were synthesized and used as an absorbent for the removal of diazinon. The developed method had advantages such as the good ability of Fe3O4@SiO2 nanocomposites to remove diazinon from aqueous solution and the magnetic separation of this absorbent that make it recoverable nanocomposite. The other advantages of these nanocomposites are rapidity, simplicity and relatively low cost.