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.
Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Dongguan 523808, China.
Environ Sci Technol. 2020 Dec 1;54(23):15433-15441. doi: 10.1021/acs.est.0c05254. Epub 2020 Nov 16.
Graphene oxide (GO) is promising for constructing next-generation high-performance membranes for water treatment and desalination. However, GO-based membranes are still subjected to low ion rejection or limited water flux. Herein, the electrokinetic effect is employed as a new strategy for the coenhancement of water flux and ion rejection through an ethylenediamine-polystyrenesulfonate intercalated graphene oxide/carbon nanotube (GO&EDA-PSS/CNT) asymmetric membrane. Benefiting from the external voltage applied across the GO&EDA-PSS layer, the electrokinetically driven water transport velocity is significantly increased from 0 to 23.7 μm s with increasing the voltage from 0 to 3.0 V. As a result, the water flux is improved from 9.1 to 17.4 L m h under a transmembrane pressure of 1 bar. Simultaneously, the rejection rate for NaCl is increased from 52.4% to 78.3%. Numerical analysis reveals that the increased rejection rate is attributed to the electrokinetic enhancements of water transport through the membrane and ion partitioning between the membrane and bulk solution. These results indicate that the assistance of the electrokinetic effect is an effective means to improve membrane filtration performance, which provides a new perspective on the design of advanced membranes for achieving high water flux and rejection efficiency.
氧化石墨烯（GO）有望用于构建新一代高性能水处理和脱盐膜。然而，基于 GO 的膜仍然存在离子截留率低或水通量有限的问题。在此，通过一种乙二胺-聚苯乙烯磺酸盐插层氧化石墨烯/碳纳米管（GO&EDA-PSS/CNT）不对称膜，采用电动效应作为提高水通量和离子截留率的新策略。得益于施加在 GO&EDA-PSS 层两侧的外电压，在跨膜压力为 1 bar 时，水的传输速度从 0 增加到 3.0 V 时，从 0 增加到 23.7 μm/s，水通量从 9.1 增加到 17.4 L·m-2·h-1。同时，NaCl 的截留率从 52.4%增加到 78.3%。数值分析表明，截留率的提高归因于膜内水传输的电动增强以及膜与主体溶液之间的离子分配。这些结果表明，电动效应的辅助是提高膜过滤性能的有效手段，为实现高水通量和截留效率的先进膜设计提供了新视角。
