小孔菱沸石选择性吸附CO2的性能研究OA

Chabazite-type(CHA)zeolite is considered to be a highly promising CO2 adsorption material due to is unique pore structure.However,the underlying adsorption kinetics of CHA zeolite still need to be studied to facilitate development of efficient adsorbents.In this study,the preparation method,CO2 adsorption kinetics,and thermodynamic properties of CHA zeolite are investigated.CHA zeolite is synthesized from hydrogen type faujasite-type(H-FAU)zeolite using a transformation method.By modulating the ratios of n(KOH)/n(SiO2),n(H2O)/n(SiO2),crystallization temperature,and crystallization time during the synthesis process,the optimal synthesis conditions for CHA zeolite are explored based on X-Ray Diffraction(XRD)and scanning electron microscopy(SEM)of the as-synthesized materials.The CO2 adsorption performance of the prepared CHA zeolite is tested and evaluated using both dynamic and static measurements.Different kinetic models are applied to analyze the kinetic behavior of the adsorption process.Among them,the Avrami equation yields a good fit to illustrate the adsorption process of studied zeolites(R2＞0.99).With increasing temperature,the adsorption process reach equilibrium more quickly due to the enhanced adsorption rate.The selectivity also increases with increasing temperature,indicating that the adsorption process of CO2 on CHA zeolite is mainly controlled by diffusion.Breakthrough data and thermodynamic analysis show that the material's interaction with CO2 is stronger than that with N2,yet the CO2 adsorption is still dominated by physical interactions.The weak adsorption strength between CO2 and CHA zeolite is conducive to gas desorption.These findings provide a theoretical support for optimizing industrial adsorption operating conditions.