Solute Diffusion through Bentonite-Polymer Composites for Containment Applications
Solute Diffusion through Bentonite-Polymer Composites for Containment Applications
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DOI：
10.1061/9780784484661.018
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发表时间：
2023-03
期刊：
影响因子：
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通讯作者：
Daniel D. Adeleke;S. A. B. Rahman;Victoria Chanez;Jenna Springer;Sarah Burghardt;K. Sample-Lord;G. Bohnhoff;Jonathan F. Hubler
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文献类型：
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作者：
Daniel D. Adeleke;S. A. B. Rahman;Victoria Chanez;Jenna Springer;Sarah Burghardt;K. Sample-Lord;G. Bohnhoff;Jonathan F. Hubler
膨润土-聚合物复合材料 (BPC) 已开发用于地质环境遏制项目，其中钠膨润土 (NaB) 可能会发生不利的化学相互作用，从而降低阻隔性能。尽管大量研究调查了 BPC 的水力传导性，但人们对 BPC 的扩散速率知之甚少。因此，本实验研究测量了浓度 (Co) 为 10 至 100 mM 的氯化钙 (CaCl2) 源溶液中溶质通过不同 BPC 材料的扩散情况。研究中评估的五种材料是 NaB（无聚合物改性）、BPC 1%–4% 和 BPC 1–8%（分别含有 4% 和 8% 聚合物的 BPC 1 型）、BPC 2%–4% 和 BPC 2%–8%（含有 4% 和 8% 聚合物的 BPC 2 型）。对于稀 CaCl2 溶液，所有四种 BPC 均表现出比未修正的 NaB 更低的 Da 值（半个数量级）。对于较高的 CaCl2 浓度 (Co= 100 mM)，BPC2 混合物相对于 NaB 仍表现出优异的性能（较低的 Da），而 BPC1 混合物表现出与未修正的 NaB 相似或在某些情况下更高的 Da 值。研究结果增强了我们考虑和预测包含 NaB 或 BPC 的安全壳屏障在一系列离子强度下的预期性能的能力。
Bentonite-polymer composites (BPC) have been developed for use in geoenvironmental containment projects where sodium bentonite (NaB) is likely to undergo adverse chemical interactions that degrade barrier performance. Although numerous studies have investigated hydraulic conductivity of BPCs, very little is known about diffusion rates through BPC. Thus, this experimental study measured solute diffusion through different BPC materials for calcium chloride (CaCl2) source solutions ranging in concentration (Co) from 10 to 100 mM. The five materials evaluated in the study were NaB (without polymer amendment), BPC 1%–4% and BPC 1–8% (BPC type 1 with 4% and 8% polymer, respectively), and BPC 2%–4% and BPC 2%–8% (BPC type 2 with 4% and 8% polymer). For dilute CaCl2solutions, all four BPCs exhibited lowerDavalues (by half an order of magnitude) than the unamended NaB. For higher CaCl2concentrations (Co= 100 mM) the BPC2 mixes still exhibited superior performance (lowerDa) relative to NaB, whereas the BPC1 mixes exhibited similar or in some cases higherDavalues than the unamended NaB. The results of the study enhance our ability to consider and predict the expected performance of containment barriers comprising either NaB or BPC for a range of ionic strengths.