双间距亚纳米复合通道g-C3N4/GO膜对一价/多价离子盐的筛分

Separation of monovalent/multivalent salts by double-pitch sub-nanocomposite channel g-C3N4/GO membrane

采用真空抽滤的方法制备二维g-C3N4/GO复合膜,其层间具有双间距亚纳米通道,有效宽度分别为~0.86和0.76 nm,双间距亚纳米通道尺寸都介于一价离子K^+与多价离子Al^3+水合直径之间,可用于精确有效地筛分一价/多价金属离子盐.在复合膜制备过程中,由于g-C3N4能够与相对应的GO纳米片发生温和的原位还原反应,从而构建有利于离子盐筛分的层间微环境.在离子盐筛分实验中,GO膜对于Na^+盐/多价金属离子盐没有筛分性能,而g-C3N4/GO可以有效分离Na^+盐/多价金属离子盐,分离因子达到10以上,其中Na^+盐/Al^3+盐的分离因子甚至高达35,表明g-C3N4/GO复合膜具有优异的一价/多价离子盐筛分能力.

A two-dimensional g-C3N4/GO composite membrane was prepared by vacuum filtration.Such a membrane exhibits double-pitch sub-nano ion channels between layers with effective widths of^0.86 and 0.76 nm,respectively.The channel sizes fall in between monovalent and multivalent ion hydration diameters and thus it can be used to accurately and efficiently screen monovalent/multivalent salts.At the same time,in the preparation process of composite membranes,since g-C3N4 can gently reduce corresponding GO nanosheets,an interlayer microenvironment favorable for salt sieving is constructed.In the ion salt sieving experiment,the GO membrane has no sieving performance for Na^+salt/multivalent salts.However,the composite membrane can effectively separate Na^+salt/multivalent ion salt,and the separation factor can reach more than 10.The Na^+salt/Al^3+salt separation factor is even as high as 35.It is shown that the g-C3N4/GO composite membrane has excellent monovalent/multivalent ion salt sieving.