Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology , Dalian University of Technology , Dalian 116024 , China.
Environ Sci Technol. 2018 Apr 17;52(8):4827-4834. doi: 10.1021/acs.est.8b00515. Epub 2018 Apr 9.
Nanofiltration (NF) has received much attention for wastewater treatment and desalination. However, NF membranes generally suffer from the trade-off between permeability and selectivity. In this work, the coenhancement of permeability and ion selectivity was achieved through tuning the surface charge and pore size of oxidized carbon nanotube (OCNT) intercalated reduced graphene oxide (RGO) membranes. With the increase of OCNT content from 0 to 83%, the surface charge and the pore size were increased. The permeability increased to 10.6 L m h bar and rejection rate reached 78.1% for NaSO filtration at a transmembrane pressure of 2 bar, which were 11.8 and 1.3 times higher than those of pristine RGO membrane. The composite membrane also showed 11.1 times higher permeability (11.1 L m h bar) and 2.9 times higher rejection rate (35.3%) for NaCl filtration. The analyses based on Donnan steric pore model suggest that the increased permeability is attributed to the combined effects of enlarged pore size and increased surface charge, while the enhanced ion selectivity is mainly dependent on the electrostatic interaction between the membrane and target ions. This finding provides a new insight for the development of high-performance NF membranes in water treatment and desalination.
纳滤（NF）在废水处理和海水淡化方面受到了广泛关注。然而，NF 膜通常存在渗透性和选择性之间的权衡。在这项工作中，通过调节氧化碳纳米管（OCNT）嵌入还原氧化石墨烯（RGO）膜的表面电荷和孔径，实现了渗透性和离子选择性的协同增强。随着 OCNT 含量从 0 增加到 83%，表面电荷和孔径增大。在跨膜压力为 2 巴时，对 NaSO 的过滤渗透率提高到 10.6 L m h bar，截留率达到 78.1%，分别是原始 RGO 膜的 11.8 倍和 1.3 倍。复合膜对 NaCl 的过滤也表现出 11.1 倍的渗透率（11.1 L m h bar）和 2.9 倍的截留率（35.3%）。基于 Donnan 空间位阻模型的分析表明，渗透性的提高归因于孔径增大和表面电荷增加的综合作用，而离子选择性的增强主要取决于膜与目标离子之间的静电相互作用。这一发现为水处理和海水淡化中高性能 NF 膜的发展提供了新的思路。
