State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China.
ACS Nano. 2014 Jun 24;8(6):6304-11. doi: 10.1021/nn501786m. Epub 2014 May 28.
Two-dimensional layered materials have joined in the family of size-selective separation membranes recently. Here, chemically exfoliated tungsten disulfide (WS2) nanosheets are assembled into lamellar thin films and explored as an ultrafast separation membrane for small molecules with size of about 3 nm. Layered WS2 membranes exhibit 5- and 2-fold enhancement in water permeance of graphene oxide membranes and MoS2 laminar membranes with similar rejection, respectively. To further increase the water permeance, ultrathin nanostrands are used as templates to generate more fluidic channel networks in the WS2 membrane. The water permeation behavior and separation performance in the pressure loading-unloading process reveal that the channels created by the ultrathin nanostrands are cracked under high pressure and result in a further 2-fold increase of the flux without significantly degrading the rejection for 3 nm molecules. This is supported by finite-element-based mechanical simulation. These layered WS2 membranes demonstrate up to 2 orders of magnitude higher separation performance than that of commercial membranes with similar rejections and hold the promising potential for water purification.
二维层状材料最近加入了尺寸选择性分离膜家族。在这里，化学剥离的二硫化钨 (WS2) 纳米片被组装成层状薄膜，并被探索作为一种用于小分子的超快分离膜，其尺寸约为 3nm。与具有类似截留率的氧化石墨烯膜和 MoS2 层状膜相比，层状 WS2 膜的水透过率分别提高了 5 倍和 2 倍。为了进一步提高水通量，使用超薄纳米线作为模板在 WS2 膜中产生更多的流体通道网络。在压力加载-卸载过程中的水渗透行为和分离性能表明，在高压下由超薄纳米线创建的通道会破裂，从而在不显著降低 3nm 分子截留率的情况下通量增加 2 倍。这得到了基于有限元的机械模拟的支持。这些层状 WS2 膜的分离性能比具有类似截留率的商业膜高出 2 个数量级，在水净化方面具有广阔的应用前景。
