Capture CO2 from N2 and CH4 by zeolite L with different crystal morphology

The performance of a zeolite is often related to its crystal morphology. In this work, the relationship between the crystal morphology of zeolite L and its gas separation performance was evaluated. Cylindrical-L (C-L: 3 × 2 μm), disk-shaped-L (D-L: 0.2 × 1.2 μm), and nanosized-L (N-L: 40 × 25 nm) were synthesized. Various characterization methods, including X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and N2 adsorption–desorption isotherms at 77 K (BET), were employed to obtain complementary information. Due to its small crystal size, the BET specific surface area (427.2 m2/g) and total pore volume (0.382 cm3/g) of N-L are significantly higher than those of D-L (339.6 m2/g and 0.116 cm3/g) and C-L (279.8 m2/g and 0.098 cm3/g). The CO2 adsorption capacity on N-L (70.7 cm3/g) increases 20.9% than that on C-L (58.5 cm3/g). The shorter channel paths in N-L permit faster diffusion and mass transfer than in C-L or D-L, as confirmed by kinetic experiments. Furthermore, breakthrough experiments indicate that N-L has great application potential for separating and capturing CO2 from power-plant flue gas, biogas, or landfill gas. [Display omitted] •The crystal morphology affects the CO2 capture from N2 and CH4.•BET surface area increases regularly by the downsizing crystal size.•The nano-sized zeolite L shows the highest CO2 uptake.•The shorter gas diffusion paths improve the mass transfer.