Containment and remediation of copper mine contamination with high concentration of heavy metals (Cu, Pb, Zn) and low pH (2–5) demand barriers with low hydraulic conductivity (k) and good chemical compatibility. To prepare modified barriers containing copper erosion by replacing Wyoming bentonite with local bentonite and screen out economic dosage, the k of 12 polymer-modified bentonites with sodium polyacrylate (PAA) or sodium-carboxymethyl cellulose (CMC) at dosages from 2 to 10%, was measured by modified fluid loss (MFL) test. The k of unmodified bentonites at 690 kPa top pressure ranged from 1.8 × 10⁻¹¹ m/s to 1.9 × 10⁻¹¹ m/s, which were reduced down to 4.6 × 10⁻¹² m/s by 5% PAA or to 5.5×10⁻¹² m/s by 5% CMC. The SEM & EDX-substantiated pore-filling effect of PAA, exfoliation of bentonite plates by PAA and CMC, and the XRD & FTIR-substantiated intercalation of CMC contributed to the decrement of available flow space and the increment of tortuosity of flow channel, and eventually k reduction. Excessive polymer (> 5%) might prop open interaggregate voids, increase pore connectivity and cause slight k increment up to 9.8 × 10⁻¹² m/s and 6.5 × 10⁻¹² m/s for 10% PAA- and 10% CMC-modified bentonites, respectively. Acidic condition (pH = 3) slightly increased the k of unmodified, 5% PAA- and 5% CMC-modified bentonite by less than 42%. At Cu²⁺ concentrations ([Cu²⁺]) of 0.38−10 mM (26 times the field concentration, 3.6 times the maximum concentration in the investigation), the k of 5% CMC-modified bentonite remained at 10⁻¹² m/s, demonstrating good chemical compatibility. This was attributed to the intercalated CMC chains, which increased interlayer repulsion, enhanced osmotic swelling of bentonite plates, and reduced cation exchange reaction with Cu²⁺ at bentonite plate surfaces. When [Cu²⁺] reached 15 mM, k of 5% CMC-modified bentonite further increased to 6.0×10⁻¹¹ m/s. This paper filled the gap of creating low permeable polymer-modified bentonite for permeants with acidic and high heavy metal content condition, which is typical near copper mines. The outcome of this research results in practically usable barrier materials, as used in a geosynthetic clay liner (GCL) or similar applications without the need of importing high-purity bentonite (e.g., Wyoming bentonite).

高浓度重金属（Cu、Pb、Zn）和低 pH 值（2-5）的铜矿污染的遏制和修复需要具有低水力传导率（k）和良好化学相容性的屏障。用当地的膨润土代替怀俄明膨润土制备含铜侵蚀的改性屏障，筛选经济用量，用聚丙烯酸钠（PAA）或羧甲基纤维素钠（CMC）在2-10%的用量下对12种聚合物改性膨润土的k值进行筛选，通过改良的滤失量（MFL）测试来测量。未改性膨润土在 690 kPa 顶压下的k范围为 1.8 × 10 ^-11  m/s 至 1.9 × 10 ^-11  m/s，降至 4.6 × 10 ^-12 通过 5% PAA 达到m/s 或通过 5% CMC 达到 5.5×10 ^{-12 m/s。}SEM 和 EDX 证实的 PAA 的孔隙填充效果、PAA 和 CMC 对膨润土板的剥离以及 XRD 和 FTIR 证实的 CMC 插层导致可用流动空间的减少和流动通道曲折度的增加，以及最终k减少。过量的聚合物 (> 5%) 可能会撑开团聚体空隙，增加孔隙连通性并导致轻微的k增量， 对于 10% PAA- 和 10% CMC-高达 9.8 × 10 ^-12  m/s 和 6.5 × 10 ^-12 m/s改性膨润土，分别。酸性条件（pH = 3）将未改性、5% PAA 和 5% CMC 改性膨润土的k略微增加不到 42%。在铜²⁺浓度 ([Cu ²⁺ ]) 为 0.38−10 mM（场浓度的 26 倍，研究中最大浓度的 3.6 倍），5% CMC 改性膨润土的k保持在 10 ^-12  m/s，表现出良好的化学相容性。这是由于插入的CMC链增加了层间排斥力，增强了膨润土板的渗透膨胀，并减少了与Cu ²⁺在膨润土板表面的阳离子交换反应。当[Cu ²⁺ ]达到15 mM时， 5% CMC改性膨润土的k进一步增加到6.0×10 ^-11 小姐。填补了铜矿附近典型的酸性、重金属含量高的渗透条件下研制低渗透聚合物改性膨润土的空白。这项研究的结果产生了实际可用的阻隔材料，如用于土工合成粘土衬垫 (GCL) 或类似应用，而无需进口高纯度膨润土（例如，怀俄明膨润土）。