Recovery of purified radiocesium from acidic solution using ammonium molybdophosphate and resorcinol formaldehyde polycondensate resin

Separation of Cs+ from acidic solution was investigated using ammonium molybdo- phosphate (AMP) based sorbents. Four sorbents including two AMP powders and two composites prepared by coating of AMP powder on polymethylmethacrylate (PMMA) beads were used in this study. Equilibrium sorption isotherms for Cs+ on AMP sorbents were determined. The effect of H+ concentration on Cs+ uptake by AMP–PMMA beads was examined. Two column runs were carried out to establish the Cs+ separation performance of AMP–PMMA beads from 1.0 M nitric acid having Cs+ concentration equivalent to 10 Ci of 137Cs per litre. Recovery of Cs+ from loaded AMPPMMA column was carried out by dissolution of AMP using NaOH solution. The feasibility of ion exchange purification of the recovered Cs+ solution was examined using resorcinol formaldehyde polycondensate resin (RFPR). The Cs+ sorption isotherm on RFPR from Cs-bearing dissolved AMP solution was determined. Purification of Cs+ from dissolved AMP solution was studied in two column runs using RFPR in loading-elution cycles. The results of these studies are useful in formulating a scheme for the recovery of purified 137Cs product from high level waste for large-scale utilization as a radiation source in industrial irradiators.

A novel sorbent prepared by coating AMP powder on PMMA beads has been found to be effective for separating Cs+ from an acidic solution. Batch sorption data show that Cs+ uptake of AMP remains unaffected even after coating on PMMA beads. The performance of AMP–PMMA column for separation of Cs+ from acidic solution is excellent. It is inferred from the column data that up to 800 Ci of 137Cs can be loaded on 1 L bed of AMP–PMMA beads from radioactive waste solution containing 10 Ci/L of 137Cs. Quan- titative recovery of sorbed Cs+ from AMP–PMMA bed is possible by complete dissolution of AMP in NaOH solution. An ion exchange process based on the use of resorcinol formaldehyde polycondensate resin in the loading–elution cycle has been developed for purification of Cs+ from Cs-bearing dissolved AMP solution. The final purified Cs+ product solution obtained after elution of Csloaded RFPR column contains substantially lower concentration of Na+ ions. The results of these studies show that ion exchange processes can be utilized for the recovery of high-purity 137Cs from acidic high level waste for use in radiation technology applications.