Removal and Separation of Some Radionuclides by Poly-acrylamide Based Ce(IV) Phosphate from Radioactive Waste Solutions

Abstract

Removal of cesium, cobalt, and europium ions from radioactive waste solutions using poly-acrylamide based Ce(IV) phosphate material was investigated using both batch and fixed bed column techniques. The effect of pH, initial metal ion concentration, and temperature had been studied. Simple kinetic and thermodynamic models had been applied from which the mechanism of the process and the thermodynamic parameters were determined. The positive values of enthalpy change, ΔH, obtained for the three metal ions confirmed the endothermic nature of the sorption process and suggested that chemisorption is the predominant sorption mechanism. The high positive values found for the entropy change, ΔS, show the increased randomness at the solid/solution interface. The obtained negative values of free energy change, ΔG, indicating the feasibility and the spontaneous nature of the sorption processes. Breakthrough data were investigated in a fixed bed column at room temperature (298 K) under the effect of various process parameters like bed depth, flow rate, and initial ion concentration. The results showed that the overall bed capacity decreased with increasing flow rate and increased with increasing initial metal ion concentrations and bed depth.