沸石基地聚合物固化核素Sr^(2+)的性能及机制  

Perpfomance and mechanism of immobilization of strontium with zeolited-based geopolymer

作　　者：徐中慧[1,2,3] 吴丹丹[1] 肖博[1] 王海龙[4] 郑磊[1] 林朋[1] 许斌[1] 

机构地区：[1]西南科技大学固体废物处理与资源化教育部重点实验室,重庆404000 [2]西南科技大学非煤矿山安全技术四川省高等学校重点实验室,重庆404000 [3]西南科技大学核废物与环境安全国防重点学科实验室,四川绵阳621010 [4]重庆三峡学院土木工程学院,重庆404000

出　　处：《南京理工大学学报》2015年第2期174-180,共7页Journal of Nanjing University of Science and Technology

基　　金：国家自然科学基金(51404200);四川省科技创新苗子项目(20132065);核废物与环境安全国防重点学科实验室开放基金(12zxnp03)

摘　　要："沸石原位转化地聚合物固化核素"可实现中低放射性核废液"吸附浓缩-固化"处置的一体化。该文在研究水玻璃模数、碱灰比和偏高岭土掺量对沸石基地聚合物抗压强度影响的基础上,探讨了沸石基地聚合物固化模拟核素锶Sr2+的性能及机制。研究结果表明,水玻璃模数在0.8~1.5时有利于制备出高强度的地聚合物;偏高岭土中硅铝成分活性大于4A沸石,但添加过量偏高岭土使反应体系硅铝比减小,反而导致其强度降低;地聚合物固化体性能优良,28d抗压强度为19 MPa;固化体在酸性和中性介质中42 d的浸出率和累积浸出分数均低于国家标准。X射线衍射(XRD)分析表明,Sr2+取代部分原料中的Na+进入地聚合物中,发生了吸附固化和胶凝相的物理包裹。红外(IR)分析表明,模拟核素锶可能通过化学键的形式进入地聚合物的三维网络结构实现固化。X射线光电子能谱(XPS)分析进一步表明,锶与含硅官能团发生了反应,促进了硅酸的聚合作用。The adsorption-solidification integration of the low and intermediate level radioactive liquid waste can be realized by the route of zeolite transformation into geopolymer in situ. In this paper,the effect of the modulus of sodium silicate,the activator ratio and the content of metakaolinite on the com- pressive strength of the zeolite-based geopolymer is explored. For further investigation, the capability and mechanism of geopolymers in solidifying simulated nuclide strontium Sr2~ are researched. The results indicate that the modulus between 0.8 and 1.5 leads to the higher compressive strength. The alumino-silicon in the metakaolinite is activated more effective than the zoelite, but overdose of metakaolinite depresses the compressive strength due to decreasing Si/A1 ratio. It is also shown that the geopolymer works well on curing strontium, for the compressive strength of solidified body is 19 MPa after curing for 28 d. The 42 d leaching rate and cumulative leaching fraction of the solidified body in acidic and neutral media are both lower than that of the national standard. X-ray diffraction （XRD） shows that the Sr2＋ takes partly place of Na~ of the raw materials, and strontium is absorption- sealed and physically sealed by geopolymer gel. Iinfrared spectrometry （IR） indicates that the simulated nuclide strontium may be cured through going into the three-dimensional network structure as chemical bonds. X ray photoelectron （XPS） further confirms that strontium incorporates in the functional groups of silicon and strontium promotes the polymerization of silicic acid.

关 键 词：4A沸石 地聚合物 模拟核素锶 固化 机制 

分 类 号：X591[环境科学与工程—环境工程]