Composite nanofiltration membrane based on covalent organic framework compound NCOF and preparation method thereof

The invention provides a composite nanofiltration membrane based on a covalent organic framework compound NCOF and a preparation method of the composite nanofiltration membrane. The preparation method comprises the following steps: firstly, synthesizing covalent organic framework compound NCOF nanoparticles under a room temperature condition, wherein the NCOF nanoparticles have the characteristics of uniform morphology and size, good monodispersity, rich hydrophilic functional groups (amine and imine) in pore channels, strong pore channel selectivity and good compatibility with polymers; and then the NCOF nanoparticles are used as a modified material of the nanofiltration membrane, so that the permeation selectivity, the structural stability and the pollution resistance of the membrane are improved. The composite nanofiltration membrane based on the covalent organic framework compound NCOF has the advantages of being large in effective filtering area, large in water flux, high in selective separation performa