多级吸附-脱附法浓缩纯化氙技术研究

Research on Multistage Adsorption-desorption Method for Enrichment and Purification of Xenon

为满足大气放射性核素监测的需求,利用氙(Xe)与二氧化碳(CO2)、氡(Rn)等组分在活性炭吸附柱内脱附行为的差异,采用多级活性炭吸附柱吸附-脱附的方法,对大气环境中的Xe(体积分数8.7×10-8)进行浓缩纯化,得到高浓度的Xe样品。研究了空气中的Xe、CO2及Rn等组分在多级活性炭吸附柱上的脱附曲线,选择Xe的脱附时段向下一级吸附柱转移吸附,对Xe进行逐级浓缩纯化。样品中Xe富集倍数可达105~106,Rn去污系数大于105,CO2体积分数低于4×10-5。此研究结果对于实现多组分混合气体中某一特定低含量组分的浓缩、纯化具有普遍指导意义。

For satisfying the demands of atmospheric radionuclide monitoring,a multistage adsorption-desorption method for enriching and purifying atmospheric xenon was studied.Because the desorption behaviors of xenon,carbon dioxide and radon are different in the process of adsorption on the column of activated charcoal,the desorption curves of xenon,carbon dioxide and radon are totally different also.Xenon can be enriched and purified by transfering the desorbed gas to the next adsorption column according to the desorption time of xenon.A xenon sample with high concentration was prepared by adsorption-desorption process in the multistage columns of activated charcoal.The enrichment coefficient of xenon is 105-106,the decontamination coefficient of radon is more than 105,and the volume fraction of carbon dioxide in the sample is lower than 4×10-5.This method can be utilized in the enrichment and purification of one given component with very low concentration in a gas mixture.