Fabrication of Fe3O4/MgAl-layered double hydroxide magnetic composites for the effective decontamination of Co(II) from synthetic wastewater

Abstract

Magnetic materials have attracted great attention as potential adsorbents for the effective removal and quick separation of contaminants in wastewater treatment. In this work, a Fe3O4/MgAl-LDH magnetic composite was prepared by chemical coprecipitation and used for the effective decontamination of Co(II) from a synthetic wastewater by an adsorption process. The characterization of XRD, TEM and FTIR indicated that Fe3O4 was successfully loaded on MgAl-LDH, providing the Fe3O4/MgAl-LDH with magnetic property which facilitates the separation of solid from aqueous solution. The adsorption of Co(II) by Fe3O4/MgAl-LDH strongly depended upon the contact time, solid content, HA or FA, pH and ionic strength. The adsorption of Co(II) reached equilibrium at 120min. The adsorption of Co(II) was dependent on ionic strength at low pH values which is controlled by outer-sphere surface complexation and/or ion exchange, while independent of ionic strength at high pH values that is attributed to the inner-sphere surface complexation. The presence of HA or FA promotes Co(II) adsorption on Fe3O4/MgAl-LDH at low pH values, whereas decreased Co(II) adsorption at high pH values. Moreover, related data show that Fe3O4/MgAl-LDH exhibits satisfactory removal efficiency for the simulated wastewater. It is worth noting that Fe3O4/MgAl-LDH could be easily separated from aqueous solution by an external magnet. So, it is clear that Fe3O4/MgAl-LDH can be potentially used as a cost-effective materials for the purification of actual Co(II)-bearing effluents.