Department of Geotechnical Engineering, Key Laboratory of Geotechnical & Underground Engineering of Ministry of Education, Tongji University, Shanghai, 200092, People's Republic of China.
School of Chemical Science and Engineering, Tongji University, Shanghai, 200092, People's Republic of China.
Environ Sci Pollut Res Int. 2020 Jul;27(20):25057-25068. doi: 10.1007/s11356-020-08895-x. Epub 2020 Apr 28.
In the Chinese high-level radioactive waste geological disposal program, Gaomiaozi (GMZ) bentonite has been selected as the potential buffer/backfill material. After the closure of the repository, the Ca-OH-type alkaline solution (evolved cement water) released by cement degradation may last for more than 100,000 years. The bentonite will undergo the corrosion of evolved cement water (ECW) for a long period. This work focuses on the sorption property of GMZ bentonite altered by ECW. Firstly, the corrosion experiments on compacted GMZ specimens with the dry density of 1.70 Mg/m were carried out under constant volume conditions at two temperatures. Then, the sorption of europium (Eu (III)) onto the corroded GMZ bentonite was studied by batch experiments. The results of batch sorption tests indicate that the altered GMZ bentonite keeps an effective removal property with the uptake of Eu (III) more than 99%. The effect of high-temperature conditions of the repository on the sorption property of bentonite is not significant. The results also suggest that the evolved cement water presents no detrimental effect on the long-term adsorption performance of bentonite even under higher temperature conditions.
在中国高放废物地质处置计划中，高庙子（GMZ）膨润土已被选为潜在的缓冲/回填材料。在处置库关闭后，水泥降解释放的 Ca-OH 型碱性溶液（演化水泥水）可能会持续超过 100,000 年。膨润土将长期受到演化水泥水（ECW）的腐蚀。本工作重点研究了 ECW 改变的 GMZ 膨润土的吸附特性。首先，在两个温度下，在恒容条件下对干密度为 1.70 Mg/m 的压实 GMZ 试件进行了腐蚀实验。然后，通过批量实验研究了 Eu（III）在腐蚀的 GMZ 膨润土上的吸附。批量吸附试验结果表明，改性 GMZ 膨润土保持了有效的去除性能，Eu（III）的去除率超过 99%。处置库的高温条件对膨润土的吸附性能影响不大。结果还表明，即使在较高温度条件下，演化水泥水也不会对膨润土的长期吸附性能产生不利影响。
