Removal of Cr(VI) from simulated electroplating wastewater by magnetite nanoparticles

Abstract

In this study, the efficiency of magnetic nanoparticles for removal of hexavalent chromium from simulated electroplating wastewater was evaluated. The nanoparticles were prepared using the sol-gel method and were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), a scanning electron microscopy energy dispersive X-ray analyzer (SEM-Edx), a particle sizer and a vibrating sample magnetometer (VSM). The results showed that synthesized nanoparticles were in the size range of 40-300 nm, had purity of about 90 percent, and had magnetization of 36.5 electromagnetic unit per gram (emu/g). In conditions including pH 2, Cr (VI) concentration of 10 mg/L, nanomagnetite concentration of 1 g/L, a shaking speed of 250 rpm and a 20 minute retention time, 82% of Cr(VI) was removed. Competition from common coexisting ions such as Na+, Ni2+, Cu2+, NO 3 -, SO4 2-, and Cl- was negligible. The adsorption data was well fitted by the Freundlich isotherm. It was concluded that magnetite nanoparticles have considerable potential for removal of Cr(VI) from electroplating wastewaters.