Evaluation of the adsorption potential of iron and manganese oxide immobilized sand for the removal of Cs(I) and Sr(II) from aquatic environment

Abstract

In this study, iron oxide immobilized sand (IIS) and manganese oxide immobilized sand (MIS) were prepared by impregnation method and employed for the removal of Cs(I) and Sr(II) from aqueous solutions. The characterizations of IIS and MIS along with the bare sand were performed with the help of SEM-EDX, FT-IR and XRD analyses. The amount of iron and manganese loaded on the sand surface were 4.52 mg/g and 1.57 mg/g, respectively. Further, the stability test showed that iron/ manganese oxide particles were strongly aggregated on the sand surface. An enhanced uptake of Cs(I) and Sr(II) were shown by IIS and MIS compared to the bare sand. The Langmuir monolayer adsorption capacity of IIS were found to be 5.102 and 1.324 mg/g for Cs(I) and Sr(II), respectively; whereas the MIS showed 2.409 and 1.277 mg/g for Cs(I) and Sr(II), respectively. The time dependent adsorption data follows pseudo second order kinetic better than pseudo first order kinetic model. The presence of other heavy metals caused a decreased in the removal of Cs(I)/Sr(II) by IIS/MIS. The effect of ionic strength studies indicate that Cs(I) and Sr(II) are weakly bound through electrostatic attraction and form outer sphere complexes on the surfaces of IIS and MIS. Further, the breakthrough curves were obtained through fixed bed column experiments and the loading capacity of the column packed with IIS or MIS were evaluated.