▎ 摘　　要

NOVELTY - Carbon dioxide separation membrane includes a support layer, a nanoparticle composite layer and a polymer layer sequentially arranged. The nanoparticle composite layer is prepared from nanoparticles and a first polymer. The nanoparticles include surface-modified nanoparticles. The surface-modified nanoparticles include at least one of crown ether-modified nanoparticles or amino-modified nanoparticles. The preparation method of the carbon dioxide separation membrane includes (a) dispersing the nanoparticles in an organic solvent (I) to prepare a nanoparticle dispersion, adding the first polymer to the nanoparticle dispersion to prepare the casting solution (I), and adding the second polymer to the organic solvent (II) to prepare the casting solution (II), and (b) coating casting solution (I) on the surface of the support layer, curing for the first time, coating casting solution (II) after drying for the first time, curing again, and drying again to obtain the separation membrane. USE - The membrane is used in carbon capture and carbon enrichment (claimed). ADVANTAGE - The carbon dioxide separation membrane has a three-layer structure, and the nano-particle composite layer is formed by matching the nanoparticles and the first polymer to solve the defect problem caused by the uneven dispersion or agglomeration of the nanoparticles in the mixed matrix membrane in the related technology. The membrane solves the problem of selectivity reduction caused by the mismatch between the polymer component and the inorganic nanoparticle phase interface in the traditional mixed matrix film. The carbon dioxide separation membrane has high selectivity to carbon dioxide and high permeability. DETAILED DESCRIPTION - Carbon dioxide separation membrane includes a support layer, a nanoparticle composite layer and a polymer layer sequentially arranged, where the carbon dioxide permeability of the carbon dioxide separation membrane is greater than 3400 Barrer, and the carbon dioxide/nitrogen selectivity coefficient is greater than 45. The nanoparticle composite layer is prepared from nanoparticles and a first polymer, where the mass percentage of the nanoparticles in the nanoparticle composite layer is 90-99.9%. The nanoparticles include surface-modified nanoparticles. The surface-modified nanoparticles include at least one of crown ether-modified nanoparticles or amino-modified nanoparticles. The preparation method of the carbon dioxide separation membrane includes (a) preparation of a casting solution by dispersing the nanoparticles in an organic solvent (I) to prepare a nanoparticle dispersion, adding the first polymer to the nanoparticle dispersion to prepare the casting solution (I), and adding the second polymer to the organic solvent (II) to prepare the casting solution (II), and (b) coating casting solution by coating casting solution (I) on the surface of the support layer, curing for the first time, coating casting solution (II) after drying for the first time, curing again, and drying again to obtain the carbon dioxide separation membrane. DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional SEM picture of the prepared carbon dioxide separation membrane. Bottom layer (100) Intermediate layer (101) Top layer (102)