Cesium ion sorption on hybrid pectin-Prussian blue beads: Batch and column studies to remove radioactive cesium from contaminated wastewater

Abstract

Hybrid sorbents composed of various ratios of Prussian blue (PB) and pectin were tested for their ability to remove cesium ions in batch and column mode. The maximum sorption capacity calculated from Langmuir isotherms was obtained for a sorbent with 50% PB additive (63.8 ± 1.7 mg g−1). The sorption kinetics studies performed at 12°C, 22°C, and 32°C and the equilibrium studies indicate physical sorption. The good sorption kinetics and the bead form of the proposed sorbents allowed column tests to be performed. Using 3 g of sorbent (50% PB), 870 mL of solution with an initial cesium content of 120 mg L−1 was purified to <2.4 mg L−1 (most of the eluate contained cesium at a level of 0.1 mg L−1). The effect of NaCl, KCl MgCl2, and CaCl2 at different concentrations on the sorption of cesium ions was also examined. The results indicated that the sorbent was also effective in a strongly saline environment, as well as in substitute ocean water and real Baltic seawater. The proposed sorbent enables safe, long-term storage of radioactive item in an air-dry, dust free state and in the smallest volume of material of high sorption capacity. This type of treatment is crucial for the disposal of radioactive waste whose activity can only be reduced by decay. Therefore, our hybrid sorbent is a promising material for the removal of (radioactive) cesium ions using either continuous or batch processes from waste aqueous solutions from a variety of sources, even those containing significant amounts of other ions.