Adsorption of CO2, CH4, and N-2 on 8-, 10-, and 12-Membered Ring Hydrophobic Microporous High-Silica Zeolites: DDR, Silicalite-1, and Beta

作者：Yang Jiangfeng; Li Junmin; Wang Wei; Li Libo; Li Jinping^*

来源：Industrial & Engineering Chemistry Research, 2013, 52(50): 17856-17864.

DOI：10.1021/ie403217n

Three hydrophobic rnicroporous high-silica zeolites, DDR (with an 8-membered ring), silicalite-1 (a 10-membered ring), and beta (a 12-membered ring) were synthesized. The Si/Al ratios were 230, 1350, and 35, respectively. The samples were characterized by X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, water vapor adsorption, and volumetric nitrogen adsorption. They were tested for their CO2, CH,, and N-2 adsorption properties at pressures of up to 10 bar at 288-313 K after activation, and the results were correlated with the Langmuir model. The heat of adsorption was calculated using the Clausius-Clapeyron equation based on the adsorption isotherms. These data were used to estimate the separation selectivities for CO2/CH4 and CH4/N-2 binary mixtures at 298 K, using the ideal adsorbed solution theory (IAST) model. Experimental results showed that DDR and beta have good selectivities for CO2/CH4, because they have narrow pores (DDR) or more balance metal ions (relatively low Si/Al ratios beta) effect separately. The synthesized silicalite-1 has the lowest SCO2/CH4 but has the most suitable orifices for methane adsorption and the highest S-CH4/N2. In addition, the breakthrough data for CH4/N-2 mixtures further indicates that silicalite-1 is more suitable for the CH4 enrichment than the commercially used sorbents zeolite-5A and 13X. From the reproducibility of CH4 and N-2 adsorption isotherms on silicalite-1, we can infer that which has the potential to be a commercial sorbent by the stable adsorption properties.

• 出版日期2013-12-18
• 单位太原理工大学