Magnesium ferrite nanoparticles as a magnetic sorbent for the removal of Mn2+, Co2+, Ni2+ and Cu2+ from aqueous solution

The aim of this research was to prepare magnesium ferrite (MgFe2O4) magnetic nanoparticles and to investigate their sorption characteristics towards Mn2+, Co2+, Ni2+, Cu2+ ions in aqueous solution. MgFe2O4 was synthesized by glycine-nitrate combustion method and was characterized by low crystallinity with crystallite size of 8.2 nm, particle aggregates of 13–25 nm, BET surface area of 14 m2/g and pore size of 8.0 nm. Sorption properties of MgFe2O4 towards Mn2+, Co2+, Ni2+, Cu2+ ions were studied using one-component model solutions and found to be dependent on metal ions concentration, contact time, pH and conditions of regeneration experiment. The highest sorption capacity of MgFe2O4 was detected towards Co2+ (2.30 mmol g1) and Mn2+ (1.56 mmol g−1) and the lowest towards Ni2+ (0.89 mmol g−1) and Cu2+ (0.46 mmol g−1). It was observed that sorption equilibrium occurs very quickly within 20–60 min. The pHzpc of sorbent was calculated to be 6.58. At studied pH interval (3.0–7.0) the sorption capacity of MgFe2O4 was not significantly affected. Regeneration study showed that the metal loaded sorbent could be regenerated by aqueous solution of 10−3 M MgCl2 at pH 6.0 within 120 min of contact time. Regeneration test suggested that MgFe2O4 magnetic sorbent can be efficiently used at least for four adsorption-desorption cycles. The high sorption properties and kinetics of toxic metal ion sorption indicates good prospects of developed sorbent in practice for wastewater treatment.