Abstract Membranes having excellent water permeability and high salt rejection are needed for developing nanofiltration technology. In the present work, a modified interfacial polymerization involving low-concentration monomers was utilized to synthesize an ultrathin polyamide (PA) layer. Carboxylated single-walled carbon nanotubes (COOH-SWCNT) were embedded into the ultrathin PA layer. The resultant additional molecular transportation pathways could reduce the trade-off effect. Besides, the morphology of ultrathin PA layer was sensitive to the presence of nanofillers, and contributed to a rougher surface of the thin film nanocomposite (TFN) membrane. As a result, the permeable area was increased, which is beneficial for water permeation. At the optimized COOH-SWCNT dosage of 0.001 wt%, even tubular crumples appeared on the fabricated membranes. Thereby, the membrane achieved an ultrahigh water permeance of 22.67 L·m−2·h−1·bar−1 while maintain a high rejection for divalent salt. For example, the rejection of Na2SO4 and MgSO4 were 95.69% and 90.03%, respectively. These excellent results were achieved using low loadings of nanofillers and under relatively low pressure (3.5 bar). The current work provides a feasible method to adjust the morphologies of NF membrane for improving its performance. And this is a promising approach due to its simplicity, and low consumptions of materials and energy.

中文翻译：

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具有管状皱褶的聚酰胺膜结合羧化单壁碳纳米管以实现高水通量

摘要 开发纳滤技术需要具有优良透水性和高脱盐率的膜。在目前的工作中，使用涉及低浓度单体的改性界面聚合来合成超薄聚酰胺 (PA) 层。羧化单壁碳纳米管（COOH-SWCNT）被嵌入到超薄 PA 层中。由此产生的额外分子运输途径可以减少权衡效应。此外，超薄 PA 层的形态对纳米填料的存在很敏感，并导致薄膜纳米复合材料 (TFN) 膜的表面更粗糙。结果，增加了渗透面积，有利于水的渗透。在优化的 COOH-SWCNT 用量为 0.001 wt% 时，制造的膜上甚至出现了管状皱褶。因此，该膜实现了 22.67 L·m-2·h-1·bar-1 的超高透水性，同时保持了对二价盐的高截留率。例如，Na2SO4 和 MgSO4 的去除率分别为 95.69% 和 90.03%。这些优异的结果是通过使用低负载量的纳米填料和在相对较低的压力（3.5 巴）下实现的。目前的工作为调整NF膜的形态以提高其性能提供了一种可行的方法。由于其简单、材料和能源消耗低，这是一种很有前途的方法。这些优异的结果是通过使用低负载量的纳米填料和在相对较低的压力（3.5 巴）下实现的。目前的工作为调整NF膜的形态以提高其性能提供了一种可行的方法。由于其简单、材料和能源消耗低，这是一种很有前途的方法。这些优异的结果是通过使用低负载量的纳米填料和在相对较低的压力（3.5 巴）下实现的。目前的工作为调整NF膜的形态以提高其性能提供了一种可行的方法。由于其简单、材料和能源消耗低，这是一种很有前途的方法。