Online Detection of Radioactive Iodine in Aqueous Systems through the Use of Scintillating Anion Exchange Resin

The objective of this research was to develop a scintillating anion exchange resin selective for monitoring 129I at concentrations at or below ∼0.4 Bq/L. One of the primary long-term risk-drivers and contaminants associated with nuclear waste sites is 129I. Synthesis of scintillating anion exchange resin consisted of diffusing a fluor, 2-(1-naphthyl)-5-phenyloxazole (α-NPO), into a polymeric resin. The resultant scintillating resin was further modified by amination with N-methyldi-n-octylamine (MDOA) to serve as an anion exchange group. Radiochromatography columns were prepared with the synthesized resin for use in a variety of flow-cell experiments utilizing a standard 129I solution in a synthetic groundwater to determine the properties (selectivity, interferences, loading efficiency, kinetics, capacity, and detection efficiency) of the resin. Column effluents were quantified by liquid scintillation. Average loading and detection efficiencies have been measured at 91 ± 9% and 50 ± 4%, respectively. Finally, batch sorption studies indicated fast iodide sorption rates (90% loading in ∼10 min) for the resin, and dynamic sorption tracer studies indicated an iodide capacity of approximately 7 800 μg/g at 10% breakthrough.