Sorption Behavior of Iodine on Calcium Silicate Hydrates Formed as a Secondary Mineral
Sorption Behavior of Iodine on Calcium Silicate Hydrates Formed as a Secondary Mineral
复制标题
次生矿物硅酸钙水合物对碘的吸附行为
DOI：
10.1115/icem2010-40089
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Hitoshi Mimura
中科院分区：
文献类型：
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作者：
Keisuke Shirai;Yuichi Niibori;Akira Kirishima;Hitoshi Mimura
考虑回填后地下水饱和的储存库系统，研究了未经干燥过程的碘在CSH凝胶中的吸附行为。在氮气浸泡的手套箱中，用CaO、SiO_2和液固比为20的蒸馏水合成CSH凝胶样品，然后在等温条件下(298K)向含有不同Ca/Si摩尔比的CSH凝胶的水溶液中加入1 mm的碘溶液。结果表明，即使在钙硅比较小的情况下(~lt；1.0)，碘在CSH凝胶上的分配系数(Kd)在未经干燥处理的CSH凝胶上也比干燥处理的大两个数量级。例如，在Ca/Si摩尔比为0.5时，Kd(ml/g)值约为380。此外，还证实了吸附行为在24小时内达到平衡。这说明在地下水饱和条件下，CSH凝胶中的次生矿物对阴离子核素的迁移有一定的延缓作用。作为比较，本研究还制备了CSH凝胶和碘的共沉淀样品，其中在固化CSH凝胶之前加入1 mM的碘溶液。这些分配系数和动力学与上述结果基本一致。
This study examined the sorption behaviors of iodine into CSH gelwithout dried processes, considering the repository system saturated with groundwater after the backfilling. In glove box saturated with N2gas, each sample of CSH gel was synthesized with CaO, SiO2, and distilled water with liquid/solid ratio 20. Then, 1 mM iodine solution is added into the aqueous solution including the CSH gel with various Ca/Si molar ratios under the isothermal condition (298 K). In the results, even if the Ca/Si ratio is relatively small (<1.0), the distribution coefficients (Kd) of iodine on CSH gel without dried processes were two-order of magnitude larger than those with dried processes. For example, the value ofKd(ml/g) was about 380 in the case of 0.5 in Ca/Si molar ratio. Furthermore, it was confirmed the sorption behavior attain equilibrium in 24 hours. These suggest secondary mineral of CSH gel would retard the migration of anionic nuclides under the condition saturated with groundwater. In comparison, this study prepared also the co-precipitated samples of CSH gel and iodine, where the 1 mM iodine solution is added before curing the CSH gel. These distribution coefficients and the kinetics almost agreed with those mentioned above.