Migration of strontium, cesium, europium and uranium from poly(methyl styrene)- and polystyrene - phosphate composites prepared using gamma radiation

Composites consisting of natural phosphate powder and two monomers (styrene or methyl styrene) have been prepared by means of gamma irradiation. The polymerization reaction was followed up using a thermogravimetric analyzer (TGA) to determine the conversion of the polymerization. Differential scanning calorimeter (DSC) was used to locate and determine the glass transition temperature (Tg) of the prepared samples. The distribution of 137Cs, 152Eu, 85Sr and 238U in a solid-aqueous system, composites of phosphate-poly(methyl styrene) and of phosphate-polystyrene in contact with groundwater, was investigated using alfa-spectrometry and fluorometry. The effects of contact time, pH, and the concentration of concurrent element (Ca) were studied. The results were compared with earlier results with phosphate alone in the solid phase. The ability of the produced composites to keep the studied radioisotopes in the solid phase is much higher than in the mineral phosphate. This improvement is more remarkable for strontium and cesium than for europium and uranium, due to their high element ratio in the solid phase in phosphate experiments

Sorption and migration of Cs, Sr, and Eu in gypsum - groundwater system

The distribution of 137Cs, 152Eu, and 85Sr in a solid/aqueous system, gypsum in contact with groundwater, was investigated using gamma-spectrometry. The sorption and migration of the radionuclides were investigated. The aqueous phase was characterized using instrumental neutron activation analysis (INAA) and high performance liquid chromatography (HPLC). The solid phases were characterized using X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The investigations included three kinds of gypsum: mineral, commercial, and own prepared gypsum. The influence of some parameters on sorption/migration of the radionuclides were studied, such as contact time, pH, and concentrations of concurrent elements. The effect of element concentration was also investigated. The results show the ability of gypsum to keep Sr and Eu in the solid phase in all three cases. The incorporation of Cs in the solid phase depends on the conditions and used materials, and varies between 93 and 97%