Preparation method and application of compact graphite phase carbon nitride film

The invention provides a preparation method of a compact graphite phase carbon nitride film. The preparation method comprises the following steps of: depositing g-C3N4 nanosheets on porous nano AAO through a vacuum suction filtration method to prepare a g-C3N4 nanosheet film, and depositing gas-phase g-C3N4 in gaps of the g-C3N4 nanosheet film through a chemical vapor deposition method by taking melamine as a precursor, so as to obtain the compact g-C3N4 film. Interception of organic matters and desalination of heavy salt water are realized by using a sub-nano-pore structure of the film material. Experimental results show that the prepared g-C3N4 film has a certain interception effect on metal ions with the hydration radius larger than that of Mg < 2 + >, so that the prepared g-C3N4 film can realize desalination of heavy salt water and has a good interception effect on macromolecular organic matters. The invention also provides application of the compact graphite phase carbon nitride film in water treatment.