Removal of Cr (VI) from aqueous solutions by nano-sized magnetite modified with SDS

Contamination of aquatic bodies with heavy metals is a serious environmental problem. Chromium is a common contaminant in ground and surface water, soil and wastewater. The aim of this study was to use magnetite nanoparticles modified by sodium dodecyl sulphate (SDS) for removal of hexavalent chromium from aqueous solutions and various factors affecting the uptake behavior such as pH, contact time, initial concentration of metal ions, adsorbent concentration, were studied. SDS modified magnetite nanoparticles were prepared by co-precipitation, and characterized by X-ray diffraction, SEM scaning electron microscopy. The XRD diffractogram showed purity of the magnetite nanoparticles and the SEM image showed that the modified magnetite particles were 50 nm. The results showed that highest adsorption (99.7%) for Cr(VI) was occurred at pH=4, adsorbent dosage 2 g/L, initial concentration Cr(VI) 10 mg/L and contact time 60 min. The adsorption data was correlated to different non-linear isotherm and kinetic models and the data fitted better to the Freundlich isotherm model. The kinetics of the Cr(VI) adsorption followed Ho (Pseudo-second-order) model. The SDS modified magnetite nanoparticles appears to be very effective at removing the Cr(VI) from aqueous solution.