Molecular simulation study of wet flue gas adsorption on zeolite 13X

Insights into Water Adsorption in Potassium-Exchanged X-type Faujasite Zeolite: Molecular Simulation and Experiment

“…(3) The water molecule accessibility of the sodalite cage, addressed by simulation, experimental, and combined tools, has been recently exhaustively reviewed by Purdue and Qiao, 47 who concluded that its accessibility in the 13X zeolite is analogous to our K−X (Si/Al = 1.1).…”

“…In the present work, we consider that the sodalite cage is accessible to water molecules for the following reasons: Three Al atoms are present within the 6-MR due to an almost strict alternation between Si and Al atoms in the K–X framework, imposed by the low Si/Al ratio (1.1), thus increasing the 6-MR diameter (∼2.8 Å) compared to the siliceous ones (∼2.2 Å), which should ease the water molecule access into the sodalite cage. The atomic radius of potassium is higher than that of sodium, and therefore, the cation–6-MR oxygen mean distance is also lengthened . Consequently, the less embedded cation in site II might let the water molecule diffuse through the 6-MR. The water molecule accessibility of the sodalite cage, addressed by simulation, experimental, and combined tools, has been recently exhaustively reviewed by Purdue and Qiao, who concluded that its accessibility in the 13X zeolite is analogous to our K–X (Si/Al = 1.1). …”

“…(2) The atomic radius of potassium is higher than that of sodium, and therefore, the cation−6-MR oxygen mean distance is also lengthened. 46 Consequently, the less embedded cation in site II might let the water molecule diffuse through the 6-MR. (3) The water molecule accessibility of the sodalite cage, addressed by simulation, experimental, and combined tools, has been recently exhaustively reviewed by Purdue and Qiao, 47 who concluded that its accessibility in the 13X zeolite is analogous to our K−X (Si/Al = 1.1).…”

Multi-factor study of the effects of a trace amount of water vapor on low concentration CO2 capture by 5A zeolite particles

“…The H 2 O molecules have a negative effect on the CO 2 adsorption amount in 5A zeolite at a high concentrations of water vapor (>0.5 ppm), similar to that reported in X-type zeolites. 35,36 This demonstrates that a large fraction of the strong CO 2 adsorption sites will disappear due to the enhancement of the short-range Lennard-Jones repulsive interactions from the water molecules at high water vapor concentrations (>0.5 ppm). Surprisingly, for the water vapor concentrations being 0.1 ppm and 0.05 ppm, the amount of adsorbed CO 2 can be enhanced by 0.7-53.4% compared to that in the dry 5A zeolite in the entire pressure range; in particular, in the low pressure range (0-10 kPa), the enhancement is in the 3.0-53.4% range.…”

Effect of Si/Al Ratio in the Faujasite Structure on Adsorption of Methane and Nitrogen: A Molecular Dynamics Study

“…The FAU zeolite structure was constructed using sorption modules at ratios of 2 and 3. The negative charge of the cell was compensated by substituting Si or Al molecules in the structure with Na + non‐framework cations 24, 30. Partial charge distribution of atoms in the structure was q Si = +2.05, q Al = +1.75, q Na = +1, and q O.Si/Al=3 = –1.1125 31.…”