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二环己基-18-冠-6(DCH18C6)可以有效地从高放废液中分离90Sr,对于减小放射性废物的危害和实现高放废物的减容有重要意义.由于在实际应用中DCH18C6处于射线照射下,其结构可能会被破坏并引起络合能力的变化,因此有必要对该配合物的辐射稳定性进行研究.本文合成了Sr(NO3)2?DCH18C6配合物晶体,并通过单晶X射线衍射(XRD)与扩展X射线吸收精细结构谱(EXAFS)等方法进行了表征,确定Sr2+与周围氧原子的配位数为10,Sr―O平均键长约为0.268 nm/0.266 nm(XRD/EXAFS).配位原子来自DCH18C6的六个氧原子以及两个作为双齿配体的硝酸根的四个氧原子.对该配合物晶体在空气中进行γ辐照,EXAFS结果表明吸收剂量为400 kGy时,Sr―O键长及配位数没有发生变化,配位结构没有被破坏,具有很好的耐辐照稳定性.显微红外光谱(Micro-FTIR)结果进一步证明辐照后冠醚环的部分C―H键氧化为羟基或羰基,但并不影响DCH18C6与Sr2+的配位结构.
Dicyclohexyl-18-crown-6 (DCH18C6) can effectively separate 90Sr from high-level liquid waste, which is of great significance to reduce the harm of radioactive waste and to achieve the reduction of high-level waste.As DCH18C6 is in practical application Therefore, it is necessary to study the radiation stability of the complex.In this paper, Sr (NO3) 2? DCH18C6 complex crystals were synthesized and characterized by single crystal X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) were used to characterize the coordination number of Sr2 + with the surrounding oxygen atoms and the average bond length of Sr-O was 0.268 nm / 0.266 nm XRD / EXAFS). The coordination atoms are derived from the six oxygen atoms of DCH18C6 and the four oxygen atoms of the two nitrate ligands as bidentate ligands. The complex crystals were gamma irradiated in air and the EXAFS results showed that the absorbed dose At 400 kGy, the length and coordination number of Sr-O did not change, the coordination structure was not destroyed, and had good radiation stability. Micro-FTIR results further proved that after irradiation Part of the crown ether ring C-H bond to hydroxyl or carbonyl oxidation, but not shadow DCH18C6 Sr2 + and coordination structures.