Calorimetric Heats of Adsorption and Adsorption Isotherms. 2. O2, N2, Ar, CO2, CH4, C2H6, and SF6 on NaX, H-ZSM-5, and Na-ZSM-5 Zeolites

作者：J. A. Dunne, M.B. Rao, Shivaji Sircar, Raymond J. Gorte, Alan L. Myers · 发表于：Langmuir · 年份：1996 · DOI：10.1021/la960496r · 被引用次数：467 · 研究领域：Zeolite Catalysis and Synthesis、thermodynamics and calorimetric analyses、Field-Flow Fractionation Techniques

Isosteric heats of adsorption and adsorption isotherms have been measured simultaneously in a calorimeter for a series of gases of increasing size and magnitude of quadrupole moment (Ar, O 2, N 2, CH 4, C 2 H 6, SF 6, CO 2 ) on adsorbents of varying pore structure and ion type (NaX, H-ZSM-5, Na-ZSM-5). Adsorption isotherms have been checked for reversibility by desorption experiments. The average experimental error in loading is ±0.6%; the average uncertainty in the isosteric heat of adsorption is ±0.5 kJ/mol. Heats of adsorption of nonpolar molecules (CH 4, C 2 H 6, SF 6 ) increase in the order NaX, silicalite, H-ZSM-5, Na-ZSM-5 at low coverage. Heats of adsorption of nonpolar molecules are almost identical on silicalite, H-ZSM-5, and Na-ZSM-5 at high coverage. Heats of adsorption of the quadrupolar molecule CO 2 increase in the order silicalite, H-ZSM-5, Na-ZSM-5, NaX. The electric field adjacent to Na + sites is 6.2 V/nm, on the basis of the difference between the heat of adsorption of CO 2 in Na-ZSM-5 and the heat of adsorption of CO 2 in silicalite.