辐照气氛对异丙氧基杯[4]冠-6辐解的影响

Influence of Atmosphere on the Radiolysis Products of BPC6 underγ-Irradiation

异丙氧基杯[4]冠-6(1,3-交替-25,27-二(2-丙氧基)杯[4]芳烃-26,28-冠-6,简称BPC6)对高放废液中的放射性Cs离子具有很好的选择萃取性能,然而在萃取过程中BPC6会受到强辐射场辐照,所以有必要研究其辐射稳定性.本文应用气相色谱(GC)、傅里叶变换显微红外(Micro-FTIR)和核磁共振(NMR)谱等手段分析了BPC6固体分别在O_2和N_2气氛下的γ辐照效应.结果表明,当剂量为1 MGy时,O_2气氛下BPC6的辐解率明显高于N_2(分别约为10.4%和2.5%),而且气体辐解产物也有很大差异,在O_2气氛下主要为H_2、CH_4、CO和CO_2,而在N_2辐照气氛下还有C_2H_4、C_2H_6、C_3H_6和C_3H_8等产物.通过综合分析气体与固体辐解产物,我们提岀BPC6在不同气氛下具有不同的辐解途径,这将为BPC6萃取体系的辐射效应研究提供新的方法与思路,加深对其辐解机理的认识.

Bis（2-propyloxy）calix[4]crown-6 （BPC6） is an effective separation agent for the removal of cesium from high-level liquid wastes, because of its high selectivity and coordination capacity toward cesium ions. BPC6 will be exposed to ionizing radiation generated by radionuclides during the treatment of high-level liquid nuclear wastes, so it is necessary to investigate the radiolysis mechanism of BPC6 under y-irradiation conditions. In this work, the radiolysis products including the gaseous and solid products of BPC6 solid were systematically assessed using gas chromatography （GC）, micro Fourier transform infrared （Micro-FTIR） spectroscopy, and nuclear magnetic resonance spectroscopy. The radiolysis ratio for BPC6 in an O2 atmosphere （approximately 10.4%） was significantly higher than that in an N2 atmosphere （approximately 2.5%）. The main radiolytic gas products of BPC6 under O2 were H2, CH4, CO, and CO2, while those under N2 were H2, CH4, CO, CO2, C2H4, C2H6, C3H6, and C3H8. Finally, a mechanism for the radiolysis of BPC6 under different atmospheres was suggested, in terms of the gas and solid radiolytic products. This work will be of significant help in understanding the degradation mechanism of the BPC6 extraction system.