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

Abstract

<jats:sec> <jats:title content-type="abstract-subheading">Purpose</jats:title> <jats:p>The purpose of this study was to the synthesis of Fe<jats:sub>3</jats:sub>O<jats:sub>4</jats:sub>@SiO<jats:sub>2</jats:sub> 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.</jats:p> </jats:sec> <jats:sec> <jats:title content-type="abstract-subheading">Design/methodology/approach</jats:title> <jats:p>The effects of different parameters including pH (2-10), contact time (1-180 min), adsorbent dosage (100-2000 mg L<jats:sup>−1</jats:sup>) and initial diazinon concentration (0.5–20 mg L<jats:sup>−1</jats:sup>) on the removal processes were studied. Finally, isotherm and kinetic and of adsorption process of diazinon onto Fe<jats:sub>3</jats:sub>O<jats:sub>4</jats:sub>@SiO<jats:sub>2</jats:sub> nanocomposites were investigated.</jats:p> </jats:sec> <jats:sec> <jats:title content-type="abstract-subheading">Findings</jats:title> <jats:p>The maximum removal efficiency of diazinon (96%) was found at 180 min with 1000 mg L<jats:sup>−1</jats:sup> adsorbent dosage using 0.5 mg L<jats:sup>−1</jats:sup> diazinon concentration at pH = 7. The experimental results revealed that data were best fit with the pseudo-second-order kinetic model (<jats:italic>R</jats:italic><jats:sup>2</jats:sup> = 0.971) and the adsorption capacity was 10.90 mg g<jats:sup>−1</jats:sup>. The adsorption isotherm was accordant to Langmuir isotherm.</jats:p> </jats:sec> <jats:sec> <jats:title content-type="abstract-subheading">Originality/value</jats:title> <jats:p>In 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 Fe<jats:sub>3</jats:sub>O<jats:sub>4</jats:sub>@SiO<jats:sub>2</jats:sub> 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.</jats:p> </jats:sec>

Iron Oxide (Fe3O4)-Supported SiO2 Magnetic Nanocomposites for Efficient Adsorption of Fluoride from Drinking Water: Synthesis, Characterization, and Adsorption Isotherm Analysis

“…Diffraction peaks were observed at 30. [58,59,61]. When the temperature increased, the crystallite size increased marginally, with irregular dispersion of the particle size.…”

“…The incremental peak was at 26.6° for SiO2 (shown by a square), and the majority of the peaks were comparable to those reported in Fe3O4 XRD patterns. As calculated using Scherer's formula [63] the crystallite sizes of the nanoparticles (Fe3O4 and SiO2) and related SiO2 NCs were around 22.55 and 56.01 nm for Fe3O4 and SiO2 NPs, respectively, and 24.88 and 23.79 nm for Fe-Si-3 and Fe-Si-5 NCs [58,59,61]. When the temperature increased, the crystallite size increased marginally, with irregular dispersion of the particle size.…”

“…A high correlation coefficient was obtained for both the Langmuir and Freundlich isotherms, as shown in Figure 3b,c. The maximum adsorption capacities (Qm) of various pollutants on Fe3O4-SiO2 and other adsorbents are documented in the literature [53][54][55][56][57][58]. It can be summarized that Fe3O4-SiO2 synthesized using various methods showed different adsorption capacity values at a working pH below 4.…”

“…Based on the observation from SEM micrographs, NCs were seen as homogeneously distributed but noticeably agglomerated particles [59]. [58,60]. Broad peaks occurring at around 1622 per cm and 3450 per cm in the spectrum were attributed to O-H bond stretching and bending vibrations of water, respectively [61].…”

“…Broad peaks occurring at around 1622 per cm and 3450 per cm in the spectrum were attributed to O-H bond stretching and bending vibrations of water, respectively [61]. The reason for the formation of broad peak is because of the aqueous medium synthesis supporting free Fe atoms and O on the NP surface [58,62].…”