Influence of mechanical activation of barium hexaferrite nano-powder on improvement of its capability for Cr (VI) ion adsorption from aqueous solution

In this study, barium hexaferrite nano-powder was prepared by chemical co-precipitation method to remove Cr (VI) ions from aqueous solutions. The effectiveness of different synthesis variable such as mechanical milling on the adsorption performance of barium hexaferrite nanao-particles was studied. The properties of samples were investigated by X-ray diffraction, scanning electron microscopy and inductively coupled plasma atomic emission mass spectrometry. Results showed that barium hexaferrite formed with the average particle size of 90 nm at a relatively low temperature of 700˚C in the sample prepared with a mixture of water/alcohol as a solvent. Also, the average particle size was decreased to 60 nm by mechanical milling of powder. It was demonstrated that barium hexaferrite nanoparticles showed the adsorption capacity of 13.25 mg/g (highest adsorption efficiency of 99.5%) at optimal conditions and with a contact time of 1 h. The adsorption data were best fitted with the pseudo-second-order kinetic model.