酵母菌对锕系核素^(239)Pu 的富集行为及减量化研究

Enrichment and Reduction of^( 239)Pu in High and Moderate Radioactive Waste Liquid by Saccharomyces cerevisiae

为了探究微生物对锕系核素的提取分离性能,利用化学预处理和湿法消解法,初步研究了模式微生物--酵母菌(Saccharomyces cerevisiae)对中高放废液中主要锕系核素^(239)Pu的富集减量效果研究.结果表明:①pH=5时,活体及灭活酵母菌对^(239)Pu的最佳吸附率均可高达99%,富集^(239)Pu后,酵母菌经灰化处理可减量97%以上.②经脱蛋白和脱乙酰化学预处理后,酵母菌对^(239)Pu的吸附能力明显下降.③随着作用时间的延长,^(239)Pu进入胞内的比例逐渐增加,吸附96 h时,约75.64%的^(239)Pu络合在细胞表面,约24.36%的^(239)Pu以稳定形式在胞内外赋存;经过6批次酵母菌吸附,^(239)Pu(Ⅲ)的放射性活度浓度从7.35×10^(6) Bq/L梯次递降至2.30×10^(3) Bq/L.④针对真实中放废液,2次酵母菌吸附后,总α放射性活度浓度可降低2个数量级,总β和总γ放射性活度浓度均仅降低10%左右.研究显示,利用酵母菌等微生物对放射性废液中锕系核素^(239)Pu的提取和分离是可能的.

In order to explore the extraction and separation performance of actinide nuclide by microorganism,the enrichment and reduction effect of model microorganism Saccharomyces cerevisiae on ^(239)Pu of actinide nuclide in medium-high discharge waste liquor was preliminarily studied by chemical pretreatment and wet digestion method.The results showed that more than 99%of ^(239)Pu removal could be achieved at pH 5 by living and dead S.cerevisiae with a microbial volume reduction of 97%after the ashing treatment.The adsorption ability was reduced significantly the ^(239)Pu biosorption capacity of S.cerevisiae with deproteinization and deacetylation treatment.The wet digestion results showed that about 75.64%of ^(239)Pu was complexed on the cell surface,while the remaining 24.36%was stabilized either inside or outside the cell after 96 h.The radioactivity of ^(239)Pu(Ⅲ)was reduced from 7.35×10^(6) Bq/L to 2.30×10^(3) Bq/L after six rounds of batch adsorption of of S.cerevisiae biosorption.The total alpha radioactivity of the real medium radioactive liquid waste could be reduced by 2 orders of magnitude with more than 98%removal of the actinide nuclide content after two rounds of S.cerevisiae biosorption.However,total beta and gamma radioactivity was only be reduced by less than 10%.The presented results indicate that bio-adsorbents such as S.cerevisiae can potentially be used to extract and separate actinides from the real radioactive wastewater.