Resistance properties of a macroporous silica-based N,N,N′,N′-tetraoctyl-3-oxapentane-1,5-diamide-impregnated polymeric adsorption material against nitric acid, temperature and γ-irradiation

During the development of the partitioning proces for removal and recovery of actinides and long-lived radioactive fission products, many powerful extractants have been proposed. The resistance of a novel silica-based N,N,N',N'-tetraoctyl-3-oxapentane-l,5-diamide (TODGA) polymeric adsorption material (TODGA/Si02-P) against nitric acid, temperature and gamma-irradiation had been investigated. The adsorption property of the treated TODGA/SiO2-P was evaluated by a 3 M HNO3 solution containing 0.01 M Nd(III). It was found that both 3 and 0.01 M HNO3 concentrations did not decrease the stability of TODGA/SiO2-P at 25DGC. The quantity of TODGA leaked from TODGA/SiO2-P was equivalent to its solubility in the corresponding HNO3 aqueous solution. The effect of 3 M HNO3 on the leakage of TODGA at 80DGC was significantly higher than that in 0.01 M HNO3 as well as in all cases at 25DGC. The amount of Nd(III) adsorbed towards the treated TODGA/SiO2-P was determined in the range of 0.143-0.148 mmol/g for the HNO3 concentration effect and 0.142-0.0506 mmol/g for the temperature effect. Gamma-Irradiation showed a more noticeable destruction effect on TODGA/SiO2-P. The content of TODGA leaked increased with an increase in the irradiation dose (ID) from 1.06 to 3.72 MGy in terms of the linear equation [TODGA] = 794.51D + 84.0. The amount of Nd(III) adsorbed onto the irradiated TODGA/SiO2-P decreased rapidly from 0.134 to 0.0438 mmol/g, which was lower than 0.153 mmol/g, the adsorption of fresh TODGA/SiO2-P for Nd(III), according to the equation QNd(iii)= -0.0301 ID + 0.160, showing that a large quantity of TODGA leaked from TODGA/SiO,-P. The adsorbed amount of Nd(III) decreased obviously in this order: the HNO3 concentration effect, temperature effect and gamma-irradiation.