Adsorption of carbon dioxide, methane, nitrogen, oxygen and argon in NaETS-4

• Published in: Microporous and mesoporous materials 2008-08, Vol.113 (1), p.268-276
• Main Authors: Pillai, Renjith S., Peter, Sunil A., Jasra, Raksh V.
• Format: Article
• Language: English
• Subjects: Adsorption; Chemistry; Colloidal state and disperse state; Exact sciences and technology; Flue gas; General and physical chemistry; Landfill gas; NaETS-4; Oxygen–argon separation; Porous materials; Surface physical chemistry
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2007.11.042

The NaETS-4 sample was synthesized and the effect of heat treatment on the adsorption of CO 2, CH 4, N 2, O 2 and Ar in NaETS-4 was studied at 373 K and 423 K. The synthesized NaETS-4 sample was characterized by scanning electron microscopy, X-ray powder diffraction and TGA/DTA analysis. The XRD pattern shows that the NaETS-4 structure starts collapsing at around 473 K. NaETS-4 degassed at 373 K shows the highest equilibrium adsorption capacity for CO 2 among the above gases and also shows higher equilibrium selectivity for CO 2 over N 2 and CH 4. NaETS-4 sample degassed at 373 K showed moderate equilibrium selectivity of 1.4 for O 2 over Ar. However, the NaETS-4 sample degassed at 423 K showed infinite selectivity for O 2 over Ar and, N 2 over CH 4 due to the pore contraction of NaETS-4 at this temperature. The equilibrium adsorption capacity for CO 2 also decreased drastically in NaETS-4 degassed at 423 K and the isotherm was irreversible. The chemisorption of CO 2 in NaETS-4 degassed at 423 K is evidenced by DRIFT spectrum of CO 2 adsorption in NaETS-4 degassed at 373 K and 423 K.