LAUSR

Abstract The aim of the present study was the synthesis of nickel ferrite magnetic nanoparticles functionalized with SiO 2 using Stober method for its application to remove lead from the water. To determine the characteristics of the synthesized magnetic nano-composite, different analysis tools were used including, Fourier transforms infrared spectrometer, X-ray diffraction analysis, Vibrating sample magnetometer and Transmission electron microscopy. Results of Vibrating sample magnetometer analysis showed that FeNi 3 @SiO 2 have typical soft magnetic traits and extraordinary para-magnetism at room temperature. The successful conjugation of SiO 2 onto the surface of FeNi 3 nanoparticles was confirmed by Fourier transform infrared spectroscopy. Transmission electron microscopy images of FeNi 3 @SiO 2 magnetic nano-composite showed particle size of around 30 nm. The optimum conditions for lead removal from the water were obtained at pH 6, 300 mg/L adsorbent dose and 20 min contact time, wherein in these circumstances the removal of lead was 87.31%. The adsorption isotherms primacy was as follows, Freundlich R 2  = 0.9889 > Langmuir R 2  = 0.9539 > Temkin R 2  = 0.9268. Also, investigation of adsorption kinetics of pseudo-first and second orders indicated that lead adsorption by FeNi 3 @SiO 2 followed the pseudo-second-order with the higher correlation coefficient of R 2  = 0.9994.