Novel Syntheses Method of Grafted Chelating Resin and Its Application Study for Depleted Zinc Production

Abstract

Depleted zinc injection into the reactor coolant system (RCS) of pressurized water reactors (PWRs) has demonstrated benefits for significantly reducing radiation fields. Liquid chromatographic separation of zinc isotopes to produce depleted zinc was attempted. A novel chelating resin PS-g-GMA@IDA containing iminodiacetic acid (IDA resins) for separation of Zn2+ and zinc isotope was synthesized by γ-ray induced co-irradiation grafting of glycidyl methacrylate (GMA) onto polystyrene (PS) spherical resin, followed by ring-opening processes with iminodiacetic acid. The obtained chelating resin PS-g-GMA@IDA before and after adsorption of Zn2+ were characterized by FT-IR spectra. This showed that the adsorption of Zn2+ by chelating resin involved two processes. Firstly, zinc ions displaced the hydrogen of the carboxyl group on chelating resin, then Zn2+ chelated with oxygen atom to form a ring structure through the coordination bonds. Adsorption abilities of PS-g-GMA@IDA were evaluated by batch adsorption experiments. The effect of pH and initial concentration on adsorption capacity of PS-g-GMA@IDA were investigated. The highest adsorption capacity 130.1 mg/g for (CH3COO)2Zn was obtained at pH = 6 within 24h when C0 were 200 ppm. EDTA-(NH4)2 was selected as eluent because of its high desorption rate of zinc. A dynamic column adsorption test was carried out at 25 °C using a 1 m column packed with PS-g-GMA@IDA, and the breakthrough occurred at about 500 ml efflunent volume. Column capacity calculated from the breakthrough curve was 56.83 mg/g. Na type PS-g-GMA@IDA was utilized to carry out column chromatographic experiment for zinc isotope separation. Under the conditions of 278±1 K, migration distance 1+9 m and EDTA-(NH4)2 as eluent, the the maximum enrichment value of 66Zn/64Zn and 68Zn/64Zn in the effluent is 1.0268 and 1.0451 respectively.