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Effects of ferrihydrite nanoparticle incorporation in cementitious materials on radioactive waste immobilization.
Journal of Hazardous Materials ( IF 12.2 ) Pub Date : 2019-04-15 , DOI: 10.1016/j.jhazmat.2019.04.053
Shuai Fan 1 , Bo Cao 2 , Ning Deng 2 , Yandi Hu 2 , Mo Li 3
Affiliation  

To enhance the long-term immobilization of radioactive wastes, ferrihydrite nanoparticles were incorporated into cementitious materials. The effects of ferrihydrite nanoparticles on the physicochemical and mechanical properties of cementitious materials and the immobilization of uranium (U), strontium (Sr) and cesium (Cs) were investigated. Adding ferrihydrite nanoparticles at 0.65%, 1.30%, 3.90% and 6.50% of cement weight slightly improved compressive strength by 5-11%, but dramatically reduced U leaching by 50-57%. The enhanced U immobilization was attributed to the strong adsorption of U by ferrihydrite nanoparticles, and the structural incorporation of U into hematite formed during ferrihydrite recrystallization. Although ferrihydrite nanoparticles had weaker effect than hematite nanoparticles on improving cement hydration and reducing permeability, they exhibit stronger U immobilization capacity. In contrast, incorporating ferrihydrite nanoparticles into cementitious materials had no significant effects on Cs and Sr leaching and no detectable adsorption of Sr and Cs. This study elucidated the fundamental differences in the interactions between ferrihydrite nanoparticles and U, Sr or Cs within cementitious systems that led to the distinctive immobilization mechanisms for these radionuclides. It generated new mechanistic understandings of U, Sr and Cs leaching from cementitious barriers modified by Fe-based nanoparticles, and proposed a new approach for enhancing long-term immobilization of U.

中文翻译:

水铁矿纳米粒子掺入胶凝材料中对放射性废物固定化的影响。

为了增强放射性废物的长期固定性,将水铁矿纳米颗粒掺入水泥质材料中。研究了水铁矿纳米粒子对胶凝材料的物理化学和力学性能以及铀(U),锶(Sr)和铯(Cs)固定化的影响。以水泥重量的0.65%,1.30%,3.90%和6.50%添加水铁矿纳米颗粒可将抗压强度提高5-11%,但可显着减少U浸出50-57%。强化的U固定化归因于三水铁矿纳米粒子对U的强吸附作用,以及U在三水铁矿重结晶过程中形成的赤铁矿中的结构结合。尽管水铁矿纳米颗粒在改善水泥水化和降低渗透率方面比赤铁矿纳米颗粒的作用弱,但它们表现出更强的U固定能力。相反,将水铁矿纳米粒子掺入胶凝材料中对Cs和Sr的浸出没有显着影响,并且对Sr和Cs的吸附也没有可检测的。这项研究阐明了胶结体系中水铁矿纳米颗粒与U,Sr或Cs之间相互作用的根本区别,从而导致了这些放射性核素的独特固定机制。它从铁基纳米颗粒改性的水泥质屏障中产生了对U,Sr和Cs浸出的新的机械理解,并提出了增强U的长期固定化的新方法。相反,将水铁矿纳米颗粒掺入胶凝材料中对Cs和Sr的浸出没有显着影响,并且对Sr和Cs的吸附也没有检测到。这项研究阐明了胶结体系中水铁矿纳米颗粒与U,Sr或Cs之间相互作用的根本区别,从而导致了这些放射性核素的独特固定机制。它从铁基纳米颗粒改性的水泥质屏障中产生了对U,Sr和Cs浸出的新的机械理解,并提出了增强U的长期固定化的新方法。相反,将水铁矿纳米颗粒掺入胶凝材料中对Cs和Sr的浸出没有显着影响,并且对Sr和Cs的吸附也没有检测到。这项研究阐明了胶结体系中水铁矿纳米颗粒与U,Sr或Cs之间相互作用的根本区别,从而导致了这些放射性核素的独特固定机制。它从铁基纳米颗粒改性的水泥质屏障中产生了对U,Sr和Cs浸出的新机制理解,并提出了增强U长期固定化的新方法。这项研究阐明了胶结体系中水铁矿纳米颗粒与U,Sr或Cs之间相互作用的根本区别,从而导致了这些放射性核素的独特固定机制。它从铁基纳米颗粒改性的水泥质屏障中产生了对U,Sr和Cs浸出的新机制理解,并提出了增强U长期固定化的新方法。这项研究阐明了胶结体系中水铁矿纳米粒子与U,Sr或Cs之间相互作用的根本区别,从而导致了这些放射性核素的独特固定机制。它从铁基纳米颗粒改性的水泥质屏障中产生了对U,Sr和Cs浸出的新的机械理解,并提出了增强U的长期固定性的新方法。
更新日期:2019-05-16
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