Department of Civil and Environmental Engineering, University of Maryland, 1161 Glenn L. Martin Hall, College Park, Maryland 20742, United States.
Environ Sci Technol. 2013 Apr 16;47(8):3715-23. doi: 10.1021/es400571g. Epub 2013 Apr 1.
We report a novel procedure to synthesize a new type of water separation membrane using graphene oxide (GO) nanosheets such that water can flow through the nanochannels between GO layers while unwanted solutes are rejected by size exclusion and charge effects. The GO membrane was made via layer-by-layer deposition of GO nanosheets, which were cross-linked by 1,3,5-benzenetricarbonyl trichloride, on a polydopamine-coated polysulfone support. The cross-linking not only provided the stacked GO nanosheets with the necessary stability to overcome their inherent dispensability in water environment but also fine-tuned the charges, functionality, and spacing of the GO nanosheets. We then tested the membranes synthesized with different numbers of GO layers to demonstrate their interesting water separation performance. It was found that the GO membrane flux ranged between 80 and 276 LMH/MPa, roughly 4-10 times higher than that of most commercial nanofiltration membranes. Although the GO membrane in the present development stage had a relatively low rejection (6-46%) of monovalent and divalent salts, it exhibited a moderate rejection (46-66%) of Methylene blue and a high rejection (93-95%) of Rhodamine-WT. We conclude the paper by emphasizing that the facile synthesis of a GO membrane exploiting the ideal properties of inexpensive GO materials offers a myriad of opportunities to modify its physicochemical properties, potentially making the GO membrane a next-generation, cost-effective, and sustainable alternative to the long-existing thin-film composite polyamide membranes for water separation applications.
我们报告了一种使用氧化石墨烯 (GO) 纳米片合成新型水分离膜的新方法,使得水可以通过 GO 层之间的纳米通道流动,而不需要的溶质则通过尺寸排阻和电荷效应被排斥。GO 膜是通过逐层沉积 GO 纳米片,然后用 1,3,5-均苯三甲酰三氯在聚多巴胺涂覆的聚砜支撑体上交联来制备的。交联不仅为堆叠的 GO 纳米片提供了必要的稳定性,以克服其在水环境中的固有不稳定性,还可以精细调整 GO 纳米片的电荷、功能和间距。然后,我们测试了用不同数量的 GO 层合成的膜,以展示其有趣的水分离性能。结果发现,GO 膜的通量在 80 和 276 LMH/MPa 之间,大约是大多数商业纳滤膜的 4-10 倍。虽然在本研究阶段,GO 膜对单价和二价盐的截留率相对较低(6-46%),但它对亚甲蓝的截留率适中(46-66%),对 Rhodamine-WT 的截留率较高(93-95%)。我们通过强调利用廉价 GO 材料的理想特性来简便地合成 GO 膜,为修饰其物理化学性质提供了无数机会,这使得 GO 膜有可能成为下一代具有成本效益和可持续性的替代物,替代现有的用于水分离应用的薄膜复合聚酰胺膜。