放射性废液中钚的耐辐射真菌吸附分离研究

快速、高效、经济地清除放射性污染是核应急处置、污染场址修复的重点研究内容。从放射性污染土壤中提取、遴选出3种耐辐射真菌F3、F7和F16,研究了其对钚的吸附分离性能。3种真菌在弱酸性(pH=0.0~4.2)溶液中对钚均有较强的吸附,吸附率随溶液pH值的增大而升高。25℃下,10 m L pH值1.0溶液中10 ng/m L的钚几乎可被3种真菌完全吸附(吸附率95%),实测F3、F7和F16对钚的平衡吸附容量分别为(11 747±539)、(17 890±757)、(11 946±477)ng/g(干菌),平衡时间约为30 min。吸附过程符合准二级动力学模型和Langmuir等温吸附模型,主要受体扩散、粒内扩散等过程控制。以0.5 mol/L的Na HCO3为解吸剂,可定量回收吸附于微生物上的钚;用3种真菌吸附回收放化实验室高盐度放射性废液中的钚,全程回收率大于99%。

Study on Sorption and Separation of Plutonium from Radioactive Waste Liquid by Radiation-resistant Fungi

The remediation of radioactive contamination in a quick, effective and economic mode is an important content in the field of nuclear emergencies and restoration of contaminated sites.In this paper, three kinds of radiation-resistant fungi, i.e.F3, F7 and F16, were separated and screened from a radioactive contaminated soil, and their soprtion performance for plutonium in aqueous solution was investigated.The results show that the three kinds of fungi have high sorption rate in pH=0.0-4.2 aqueous solution and increase with pH.At pH=1.0, 10 ng/mL plutonium in the aqueous solution is almost entirely absorbed (sorption rate>95%) at 25 ℃ with equilibrium sorption capacity of (11 747±539), (17 890±757) and (11 946±477) ng/g thalli (dry weight) for F3, F7 and F16 respectively within 30 min.Controlled by bulk diffusion and intraparticle diffusion process, the sorption process fits the pseudo-second-order kinetic model and Langmuir isotherm.Plutonium in the fungi can be quantificationally desorbed by 0.5 mol/L NaHCO3.More than 99% of plutonium is reclaimed by these fungi used for treatment of the high salinity radioactive waste liquid from a radiochemical laboratory.