Wei Yangyang, Wang Jian, Li Hao, Zhao Man, Zhang Huifeng, Guan Yipeng, Huang Hai, Mi Baoxia, Zhang Yushan
The Institute of Seawater Desalination and Multipurpose Utilization, State Oceanic Administration Tianjin 300192 China
Department of Civil and Environmental Engineering, University of California Berkeley CA 94720 UK
RSC Adv. 2018 Apr 11;8(25):13656-13663. doi: 10.1039/c8ra01916a.
A tremendous quantity of brackish water with a high proportion of divalent cations is in great need of water softening. Layer-stacked graphene oxide membranes show potential in membrane processing due to their molecular sieving properties, but show poor selective retention of cations due to unstable interlayer spacing and electrostatic interaction. In this study, a partially reduced graphene oxide (prGO) and chitosan (CS) nanohybrid membrane (prGO-CS) was fabricated to achieve the selective retention of divalent cations by adjusting the configuration and controlling the surface charge. The prGO-CS membrane, which included a CS skin and embedded prGO sheets, showed a performance boost of 98.0% rejection of Mg and 95.5% rejection of Ca when compared with a CS membrane. The membrane showed good water softening performance for brackish water under low operation pressure with a high Na/Mg selectivity of 33.8. The excellent performance was attributed to the dense structure and positive charge of prGO-CS.
大量含有高比例二价阳离子的微咸水急需进行水软化处理。层叠氧化石墨烯膜因其分子筛分特性在膜处理方面展现出潜力，但由于层间距不稳定和静电相互作用，其对阳离子的选择性保留较差。在本研究中，制备了一种部分还原氧化石墨烯（prGO）和壳聚糖（CS）的纳米复合膜（prGO-CS），通过调整结构和控制表面电荷来实现对二价阳离子的选择性保留。与CS膜相比，包含CS皮层和嵌入prGO片层的prGO-CS膜对Mg的截留率提高了98.0%，对Ca的截留率提高了95.5%。该膜在低操作压力下对微咸水表现出良好的水软化性能，Na/Mg选择性高达33.8。优异的性能归因于prGO-CS的致密结构和正电荷。
