▎ 摘　　要

NOVELTY - Self-supporting two-dimensional film comprises film-forming material stacked to film, where the film-forming material comprises graphene oxide or MXene, and the thickness of self-supporting two-dimensional film is 0.2-5 mu m. USE - Self-supporting two-dimensional film useful in membrane separation, such as nanofiltration (claimed). ADVANTAGE - The self-supporting two-dimensional film realizes excellent filtering function, determines the thickness of self-supporting two-dimensional membrane by amount of film-forming material filtered, controls the film-forming material by controlling amount of film-forming material, and realizes the control of film thickness. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method of preparing the self-supporting two-dimensional film, involving (a) preparing precursor dispersion and film-forming material dispersion, (b) filtering obtained precursor dispersion liquid by substrate filter membrane to form composite film with surface covered with precursor layer, and (c) filtering film-forming material dispersion liquid by composite membrane, drying and stripping to obtain self-supporting two-dimensional film.