Polymer solution injection has emerged as a promising method for the remediation of NAPL (non-aqueous phase liquids)-contaminated aquifers. This technique enhances recovery efficiency by modifying viscous forces, stabilizing the displacement front, and minimizing channeling effects. However, there remains a significant gap in understanding the behavior of polymer solutions, particularly those with different molecular weights (MW), for mobilizing DNAPL (dense non-aqueous phase liquids) trapped in heterogeneous aquifers, especially within low-permeability layers. In this study, we address this gap by investigating the mobilization of DNAPL lenses confined by low-permeability layers through the injection of polyethylene oxide (PEO) polymers of varying MW. PEO solutions with MW of 5 M (million) and 8 Mg/mol displayed shear-thinning behavior for shear rates of 0.01 to 100 s-1, while the 1 Mg/mol solution showed shear-thinning below 10 s-1 and Newtonian behavior above. PEO solutions in porous media exhibit Newtonian behavior at low-to-moderate shear rates for all MWs, likely due to confinement-limited entanglement.

中文翻译：

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使用剪切稀化 PEO 聚合物在非均质含水层中移动 DNAPL 透镜：实验和数值研究


聚合物溶液注入已成为修复 NAPL（非水相液体）污染含水层的一种很有前途的方法。该技术通过修改粘性力、稳定位移前沿和最小化沟流效应来提高恢复效率。然而，在了解聚合物溶液的行为方面仍然存在很大差距，尤其是那些具有不同分子量 （MW） 的聚合物溶液，用于移动被困在非均质含水层中的 DNAPL（致密非水相液体），尤其是在低渗透层中。在这项研究中，我们通过研究通过注射不同 MW 的聚环氧乙烷 （PEO） 聚合物来移动受低渗透层限制的 DNAPL 透镜，从而解决了这一差距。MW 为 5 M（百万）和 8 Mg/mol 的 PEO 溶液在 0.01 至 100 s-1 的剪切速率下表现出剪切稀化行为，而 1 Mg/mol 溶液在 10 s-1 以下表现出剪切稀化，在高于 10 s-1 时表现出牛顿行为。对于所有 MW，多孔介质中的 PEO 溶液都表现出低到中等剪切速率的牛顿行为，这可能是由于约束限制的纠缠。