▎ 摘　　要

NOVELTY - Two-sided nanofiltration membrane with positive and negative electrical heterogeneity structure comprises base film and upper and lower nano filtration surface deposited and assembled at one side of the base film, where the two-side nano filtration surface is orderly deposited on the base film of a positive electric sheet layer and a negative electric sheet layer, or a negative electric sheet layer and a positive electric sheet layer which are orderly deposited on the base film; the material of anode layer is phosphorylated graphene oxide (PGO) modified by quaternization, the material of cathode layer is graphene oxide (GGO) modified by carboxylation, where the deposition mass ratio of PGO and GGO on the base film is 1-4: 5-2. USE - The nanofiltration membrane is useful as magnesium-lithium separation membrane for seawater desalination (claimed) and lithium extraction from salt lake brine. ADVANTAGE - The two-sided nanofiltration membrane with positive and negative electrical heterogeneity structure can efficiently realize the interception of the divalent ion and the separation of the magnesium-lithium.