Synthesis of 2,4-dinitrophenylhydrazine loaded sodium dodecyl sulfate-coated magnetite nanoparticles for adsorption of Hg(II) ions from an aqueous solution

Background: The rapid increase in agricultural and industrial development has made heavy metal pollution a serious environmental problem and public health threat; therefore, removal of heavy metals from water is important. The current study prepared DNPH@SDS@Fe3O4 nanoparticles as a novel and effective adsorbent for removal of Hg(II) ions from an aqueous solution. Methods: A selective adsorbent for Hg(II) was synthesized by coating Fe3O4 nanoparticles with sodium dodecyl sulfate which was further functionalized with 2,4-dinitrophenylhydrazine (2,4-DNPH). The synthesized nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), scanning electron microscopy (SEM) and SEM-EDXSt. The effects of pH, dose of adsorbent and shaking time on adsorption capacity were investigated. The kinetics and equilibrium of adsorption of the metal ions were thoroughly studied. Results: SEM showed that the size of the nanoparticles was 20 to 35 nm. The maximum adsorption capacity for Hg(II) was 164.0 mg g(-1) for an adsorbent dose of 0.04 g at pH 7.0, 25 degrees C and the initial metal concentration was 25 mg L-1, which was greater than for most adsorbents previously examined for Hg(II) adsorption. Adsorption experimental data showed good correlation with the pseudo-second-order model and Langmuir isotherm model. Conclusion: The results indicated that the DNPH@SDS@Fe3O4 nanoparticles are an efficient adsorbent for removal of heavy metal from wastewater.