Abstract: The adsorption separation of CO2，CH4 and N2 was studied via volumetric measurements of β-zeolite samples with different SiO2/Al2O3 ratios at 273 and 303 K. Results showed that all the obtained adsorption isotherms are well correlated with the Langmuir-Freundlich model. For a certain sample，the adsorption capacity for CO2 is much higher than that for CH4 and N2. The adsorption capacity for CO2 increases with the decrease in SiO2/Al2O3 ratio under same temperature and pressure. The Henry law′s constant and adsorption equilibrium selectivity of CO2，CH4，and N2 on different β-zeolite samples were calculated via Virial equation，showing that the β-zeolite samples have higher equilibrium selectivity for CO2 over N2 and CH4. The selectivity of CO2 over N2 and CH4 increases with the decrease in SiO2/Al2O3 ratio. Therefore，the β-zeolite sample with a low SiO2/Al2O3 ratio is a good candidate for the separation of carbon dioxide from its mixture with methane and nitrogen. The isosteric adsorption heat for CO2，CH4 and N2 calculated by Clausius-Clapeyron equation is independent with the increase of adsorption loading，which indicates thatβ-zeolite is an energetically homogenous adsorbent.

摘要： 采用体积法在273 K和303 K温度下对CO2、CH4和N2在不同硅/铝比的β沸石上的吸附分离性能进行了研究。实验结果表明，Langmuir-Freundlich模型能够较好地拟合吸附实验数据；同一样品上，CO2的吸附量要大于CH4和N2的吸附量；随着硅铝比的减小CO2的吸附量增加，而硅/铝比对CH4和N2的吸附量的影响较小。通过结合Virial方程计算CO2、CH4和N2在不同硅/铝比β沸石上的亨利定律常数和吸附选择性，发现所研究样品对CO2/CH4和CO2/N2均具有很高的吸附选择性，随着样品硅/铝比的减小，CO2/CH4和CO2/N2的吸附选择性显著增加，说明较低硅/铝比β沸石有利于分离CO2。用Clausius-Clapeyron方程求得CO2、CH4和N2在不同硅/铝比的β沸石上的吸附热与吸附量无关，表明β沸石是一种表面势场均匀的吸附剂。