High-Pressure Methane Adsorption on NaX and NaY Zeolites with Different Si/Al Ratios

Abstract

One method of increasing the storage capacity of compressed natural gas, an alternative for vehicular fuel, is by adsorbing it on to microporous solids such as zeolites or activated carbons. NaX and NaY zeolites with different Si/Al ratios have been synthesized and characterized. Experimental adsorption isotherms for CH4 on these zeolites have been obtained at different temperatures over a pressure range of 0–5 MPa using a high-pressure volumetric apparatus. Isosteric heats of adsorption have been estimated and the isotherms analyzed applying a statistical thermodynamic model. The efficiency of this solid as a methane storage system has been evaluated and compared with other sorbents. Encouraging results have been obtained.

Different Adsorption Behaviors of Methane and Carbon Dioxide in the Isotypic Nanoporous Metal Terephthalates MIL-53 and MIL-47

“…This suggests gas interactions with a relatively homogeneous pore system as is the case, for example, during the adsorption of methane on known homogeneous adsorbents such as the purely siliceous zeolite silicalite . The values observed of 17 kJ·mol -1 for both MIL-53 samples are similar to the values obtained for the adsorption of methane on NaY zeolite (17−17.8 kJ·mol -1 ). , …”

“…21,23 This relatively weak interaction with the MIL-53 samples is also confirmed by the possibility of removing the totality of the CO 2 under a 5 mbar vacuum. The total amounts adsorbed (∼10 mmol‚g -1 ) at 30 bar are well above those obtained typically with zeolites 21,[23][24][25] and comparable with the microporous carbons [26][27][28] and close to the best MOFs. 29 Such a step in the adsorption isotherm during gas storage is uncommon, but some related phenomena have previously been observed for other systems.…”

“…23 The values observed of 17 kJ‚mol -1 for both MIL-53 samples are similar to the values obtained for the adsorption of methane on NaY zeolite (17-17.8 kJ‚mol -1 ). 21,24 Turning to CO 2 , the striking feature of the adsorption isotherms obtained with both MIL-53 samples is the presence of a step at around 6 bar. The apparatus does not currently permit desorption at the present although such studies will be undertaken shortly.…”

MIL-96, a Porous Aluminum Trimesate 3D Structure Constructed from a Hexagonal Network of 18-Membered Rings and μ3-Oxo-Centered Trinuclear Units

“…The adsorption isotherm of methane is far more linear with an initial interaction of 16 kJ·mol -1 which rapidly drops. The amount adsorbed for each gas at 10 bar (4.4 mmol·g -1 for CO 2 and 1.95 mmol·g -1 for CH 4 ) is below many materials including zeolites, − activated carbons, − and other MOF , materials.…”

Energetic Characterization of Faujasite Zeolites Using a Sensor Gas Calorimeter

“…Mentasty et al investigated the adsorption of methane on a NaX and a NaY zeolite with different Si/Al ratios at temperatures between 258-298 K and pressures between 0 MPa and 50 MPa [26]. Both the loadings and the heats were found to be lower on the NaY zeolite with a higher Si/Al ratio compared to the NaX zeolite.…”