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| 还原条件下膨润土胶体稳定性的研究 |
| Study on the stability of bentonite colloids under reducing conditions |
| 投稿时间：2024-03-04 修订日期：2024-03-27 |
| DOI： |
| 中文关键词: 膨润土胶体 SeO32-浓度 手套箱 迁移预测 |
| 英文关键词:bentonite colloids SeO32- concentration Glove box migration prediction |
| 基金项目:国家自然科学基金结余经费后续研究项目(230XJZ129)；国家自然科学基金(U1703123)；湖南省自然科学基金(2020JJ40522) |
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| 中文摘要: |
| 还原条件下,膨润土胶体的稳定性与环境中放射性核素在花岗岩裂隙中的吸附迁移息息相关。在高放废物地质处置的安全评价中,核素Se作为一种核素的裂变产物,在地下水环境中以多种价态形式存在,还原环境中易被还原为难溶性物质,这对于膨润土胶体的稳定性及其与核素的迁移都有重要影响。目前在还原环境中膨润土胶体稳定性与SeO32-之间的关系未得到很好的揭示。本文主要模拟在还原条件下,探究离子强度(Na+、Ca2+)、pH值的对膨润土胶体稳定性影响效果,重点开展了SeO32-浓度的影响试验。结果表明,碱性条件下,膨润土胶体的稳定性较好；当SeO32-的浓度高于8×10-3 mol/L时,膨润土胶体的粒径变化显著；相对于阳离子(Na+、Ca2+)的CCC值(1×10-2 mol/L、4×10-3 mol/L),SeO32-的CCC值较小,对胶体粒径的影响也较小；当SeO32-的浓度降至2×10-3 mol/L时,膨润土胶体的粒径可以恢复到试验初始状态时胶体的粒径。 |
| 英文摘要: |
| The stability of bentonite colloids under reducing conditions is closely related to the adsorption and migration of radionuclides from the environment in the granite fissures. In the safety evaluation of geological disposal of high-level waste, nuclide Se, as a fission product of nuclides, exists in the groundwater environment in multiple valence forms, and is easily reduced to insoluble substances in the reducing environment, which has an important impact on the stability of bentonite colloids and their migration with nuclides. At present, the relationship between bentonite colloid stability and SeO32- in the reducing environment has not been well revealed. In this paper, we mainly simulate the effect of ionic strength (Na+, Ca2+) and pH on the stability of bentonite colloids under reducing conditions, focusing on the effect of SeO32- concentration. The results show that the stability of bentonite colloids is better under alkaline conditions; when the concentration of SeO32- is higher than 8×10-3 mol/L, the particle size of bentonite colloids changes significantly; compared with the CCC values of cations (Na+, Ca2+) (1×10-2 mol/L, 4×10-3 mol/L), the CCC value of SeO32- is small, and the influence on the particle size of the colloids is small; when the concentration of SeO32- is reduced to 2×10-3 mol/L, the particle size of the bentonite colloid can be restored to that of the colloid at the initial state of the test. |
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