Study on preparation of amino-carbon dots/polyimide mixed-matrix membrane and its CO₂ separation performance

Amino-carbon dots prepared by hydrothermal method are compounded with polyimide to obtain mixed-matrix membranes. The effects of doping concentration of amino-carbon dots on the morphology and structure of membranes are investigated by SEM, FT-IR, XRD and DSC. The amino groups on the surface of the amino-carbon dots could provide alkaline environment, which increases the free volume in the membranes and then promotes CO₂ transfer. When the doping concentration of amino-carbon dots is 0.3%, the CO₂ separation performance of mixed-matrix membranes is best. The permeability of CO₂, CH₄ and N₂ are 85.87 barrer, 1.69 barrer and 2.62 barrer, and the selectivity of CO₂/CH₄ and CO₂/N₂ are 50.81 and 32.77, respectively.