Abstract
MOF-5, also known as isoreticular MOF-1 (IRMOF-1) was successfully synthesized with diethyl formamide (DEF) as a solvent using modified procedures aiming at improving its crystal structure, pore texture and ultimately the hydrogen adsorption performance. The MOF-5 adsorbent was characterized with nitrogen adsorption for pore textural properties, scanning electron microscopy for crystal structure, and XRD for phase structure. Hydrogen adsorption in MOF-5 was measured at low pressure in a volumetric unit at 77 K, 194.5 K and 298 K and at hydrogen pressure up to 120 bar and 77 K in a gravimetric adsorption unit. The MOF-5 synthesized in this work has ideal pore textural properties with a large Langmuir (3917 m2/g) and BET specific surface area (2449 m2/g), a median pore size of 8.6 Å and a pore volume of 1.39 cm3/g. The MOF-5 adsorbent synthesized in this work has a hydrogen adsorption capacity of 1.46 wt.% at 77 K and 1 bar, an excess hydrogen adsorption capacity of 6.9 wt.% at 77 K and 100 bar, and an absolute hydrogen adsorption capacity of 11.8 wt.% at 77 K and 120 bar. Hydrogen diffusivity in MOF-5 estimated from the adsorption kinetic data measured at low pressure are 2.4 × 10-5 cm2/s, 5.2 × 10-5 cm2/s and 6.0 × 10-5 cm2/s at 77 K, 194.5 K and 298 K, respectively. The activation energy for hydrogen diffusion and the isosteric heat of adsorption for hydrogen adsorption in MOF-5 are 0.8 kJ/mol and 2.2-2.6 kJ/mol, respectively.
Original language | English (US) |
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Pages (from-to) | 280-287 |
Number of pages | 8 |
Journal | Separation and Purification Technology |
Volume | 64 |
Issue number | 3 |
DOIs | |
State | Published - Jan 12 2009 |
Externally published | Yes |
Keywords
- Adsorption
- Equilibrium
- Hydrogen
- Kinetics
- MOF-5
ASJC Scopus subject areas
- Analytical Chemistry
- Filtration and Separation