Porous graphene-based membranes for water purification from metal ions at low differential pressures.
Porous graphene-based membranes for water purification from metal ions at low differential pressures.
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DOI：
10.1039/c5nr09278g
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发表时间：
2016-05
期刊：
影响因子：
6.7
通讯作者：
Jaewoo Park;P. Bazylewski;G. Fanchini
中科院分区：
文献类型：
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作者：
Jaewoo Park;P. Bazylewski;G. Fanchini
本文介绍了一种基于弱氧化和纳米多孔石墨烯的新一代水净化膜。这些膜显著降低了反渗透净水的高能量需求。它们结合了多孔和非氧化单层石墨烯的优点，在相对较低的压差下提供节能的水过滤，以及高度氧化的氧化石墨烯，在杂质吸附方面表现出高性能。在报道的制造工艺中，在打开（亚）纳米尺寸的石墨烯孔之前，用热退火的胶体二氧化硅密封并置的几层石墨烯薄片之间的泄漏。这项工作首次探索了这一过程，其结果是纳米多孔石墨烯薄片在边缘防水，而不会阻塞（亚）纳米孔。使用这种方法，通过基于尺寸的孔隙排斥和孔隙边缘吸附的结合，从水中去除杂质。石墨烯薄片的薄度使这些膜能够在低至30千帕的压差下，从浓度为百万分之几的金属离子中净化水，优于现有的石墨烯或氧化石墨烯净化系统。
A new generation of membranes for water purification based on weakly oxidized and nanoporous few-layer graphene is here introduced. These membranes dramatically decrease the high energy requirements of water purification by reverse osmosis. They combine the advantages of porous and non-oxidized single-layer graphene, offering energy-efficient water filtration at relatively low differential pressures, and highly oxidized graphene oxide, exhibiting high performance in terms of impurity adsorption. In the reported fabrication process, leaks between juxtaposed few-layer graphene flakes are sealed by thermally annealed colloidal silica, in a treatment that precedes the opening of (sub)nanometre-size pores in graphene. This process, explored for the first time in this work, results in nanoporous graphene flakes that are water-tight at the edges without occluding the (sub)nanopores. With this method, removal of impurities from water occurs through a combination of size-based pore rejection and pore-edge adsorption. Thinness of graphene flakes allows these membranes to achieve water purification from metal ions in concentrations of few parts-per-million at differential pressures as low as 30 kPa, outperforming existing graphene or graphene oxide purification systems with comparable flow rates.