Recently, Professor Wang Jingtao's team from the School of Chemical Engineering, Zhengzhou University, has made new progress in the separation of charged substances (all kinds of salts, dyes, organic acids / bases). The team innovatively designed the charged heterostructure nanosheets, and assembled the vacuum extraction filter into a two-dimensional layered membrane. The serious resource and environmental problems promote the rapid development of advanced membrane separation technology. However, the developed separation membrane is usually a homogeneous charged membrane, and the counterions in the solution can easily form a double electric layer on the channel wall, which compresses the mass transfer space and weakens the ion-channel interaction, restricting the ion interception effect of the membrane.