Preparation and ion exchange studies of cesium and strontium on sodium iron titanate

Abstract

Sodium iron titanate (NaFeTiO) inorganic ion exchanger was synthesized and the ion exchange behaviour of cesium, strontium and europium ion on NaFeTiO was studied. The sodium iron titanate was prepared by the hydrolysis of tetraethyl ortho titanate with sodium hydroxide in the presence of ferric chloride at the Ti/Fe mole ratio of 25.7. The ion exchange material was characterized by elemental analysis, sodium exchange capacity, X-Ray diffraction, thermogravimetry, and Raman spectroscopy. The distribution coefficient (Kd, mL/g) of cesium, strontium and europium on NaFeTiO was measured as a function of pH of the aqueous phase, duration of equilibration, concentration of sodium, cesium, strontium and europium ion in aqueous phase. The Kd of cesium gradually increased with increase of pH, and that of strontium also increased up to pH 6 followed by saturation in Kd values. However, the distribution coefficient of europium increased up to pH 4 followed by the precipitation of europium at higher pH values. The rate of ion exchange of cesium and strontium on NaFeTiO was rapid in the initial stages of equilibration followed by the establishment of equilibrium occurring after 200 min. The kinetics of extraction was fitted in to pseudo-first order and -pseudo-second order rate equations. The NaFeTiO was found to follow the ion exchange mechanism, in which the sodium ion from NaFeTiO was exchanged with cesium or strontium ion from aqueous phase. The strontium exchange capacity on NaFeTiO was determined to be 233 mg g−1. The loaded metal ions was recovered using 0.5 M nitric acid.