Removal of copper, nickel and zinc by sodium dodecyl sulphate coated magnetite nanoparticles from water and wastewater samples

In the present study, sodium dodecyl sulphate-coated Fe3O4 nanoparticles (SDS-Fe3O4 NPs) were applied to remove Cu(II), Ni(II) and Zn(II) ions from water and wastewater samples. The effects of pH of solution, SDS, Fe3O4 NPs and salt addition on removal efficiency of the metal ions were investigated and optimized. Salt addition has a negative effect on the removal efficiency of the metal ions, thus extraction follows the ion exchange mechanism. The results showed that the adsorption process onto the adsorbent is very fast under optimum conditions and nearly 1 min of contact time was found to be sufficient for completion of the metal ions' adsorption. Adsorption equilibrium of the metal ions reveals that data were fitted well to the Langmuir isotherm. Also, the maximum monolayer capacity, qmax, obtained from the Langmuir isotherm was 24.3, 41.2 and 59.2 mg g−1 for Cu(II), Ni(II) and Zn(II), respectively. Desorption experiments by elution of the adsorbent with methanol show that the SDS-Fe3O4 NPs could be reconditioned without significant loss of its initial properties even after three adsorption-desorption cycles. Finally, application of the SDS-Fe3O4 NPs as efficient adsorbent material for removal of the metal ions from Iran Khodro's wastewater samples was investigated and satisfactory results were obtained.