云母矿物的风化过程对放射性铯吸附行为的微观调控机制

As is well known, micaceous minerals are very important to control radiocesium migration, transformation and fate behaviors in the environment; however, it remains unclear how the weathering process affects on the environmental behaviors of radiocesium. In this proposal, the typical micaceous minerals with various weathering degrees, i.e., muscovite, biotite and phlogopite, were selected to predominantly explore the sorption-desorption processes， occurrences states and bioavailability of radiocesium at a molecular scale combining batch (such as artificial weathering, sorption, extraction and modelling experiments) and spectroscopic approaches (main extended X-ray absorption fine structure (EXAFS), µ-X-ray fluorescence (µ-XRF) and high resolution transmission electron microscope (HRTEM)). The effect of environmental factors on the structures of the micaceous minerals was estimated firstly before and after weathering. The regulation mechanism on radiocesium sorption behaviors was explored on the micaceous minerals with various weathering processes. The relationship between radiocesium environmental behaviors and micaceous mineral weathering process will be clarified combining the batch and spectroscopic experiments. Finally, a general adsorption model for radiocesium will be constructed to quantitatively describe and predict radiocesium behaviors in a complicated environmental medium. The findings in this proposal can be expected to essentially illustrate radiocesium environmental behaviors such as spatial distribution, migration and transformation at the molecular scale. It could also offer important and necessary technical supports to the remediation of radioactive contaminated areas.

众所周知，云母矿物对放射性铯（RCs）的迁移、转化、归趋等环境化学行为起到至关重要的作用；然而，云母矿物风化过程对RCs环境化学行为的微观调控机制仍不清楚。本项目选取典型云母矿物（白云母、黑云母和金云母）作为重点研究对象，结合宏观（模拟风化、吸附和连续提取）和微观（HRTEM、EXAFS和µ-XRF）的实验方法，从分子水平上系统研究RCs在典型云母矿物及其风化产物上的吸附-解吸过程、微观赋存状态等环境化学行为，考察环境因素和RCs吸附过程对云母矿物自身结构的影响，剖析RCs吸附行为对云母矿物风化过程的响应，揭示云母矿物风化过程对RCs吸附行为的微观调控机制。旨在构建能够定量描述和预测RCs在不同环境介质中的吸附模型，为准确、有效评价和预测放射性污染区域RCs的迁移、转化和空间分布等环境化学行为提供重要的理论基础，亦可为放射性污染区域环境的修复和治理提供技术支持。

众所周知，云母矿物对环境系统中放射性铯（RCs）的迁移、转化、循环等过程起到至关重要的作用。在长时间尺度上，云母矿物在环境系统中不断发生风化作用，导致云母矿物的结构和类型均发生显著变化，这一过程对RCs的环境化学行为的影响却不清楚。本项目系统研究了RCs在典型云母类矿物及其风化产物表面上的吸附过程、微观赋存状态等，发现风化度不同的云母矿物对RCs的吸附能力、吸附形态以及RCs的环境活性等均存在较大的差异（总体来说，风化程度越高，云母矿物对RCs的吸附能力越强、环境活性越低；也就是说云母矿物的风化有利于RCs固定）；阐明了环境因素和RCs吸附过程对云母矿物自身结构的影响，发现吸附RCs后的云母矿物抵御风化作用的能力更高，而风化作用则促进RCs形成更加稳定的吸附形态；进而揭示了云母矿物风化过程与其吸附RCs机制的内在联系。相关研究成果可为准确、有效评价和预测放射性污染区域RCs的空间分布、迁移、转化等环境行为提供总要的理论基础，亦可为区域放射性污染的修复和治理提供技术支持。