吸附
沸石咪唑盐骨架
锌
咪唑酯
化学
锌化合物
无机化学
金属有机骨架
材料科学
核化学
物理化学
有机化学
作者
Sana Ahmed Khalil,Nadhem Missaoui,Raedah A.S. Alatawi,Ali A. Keshk,Obaidallah Alatawi,Tahani A. Albalawi,Andrew J. Gross
标识
DOI:10.1002/slct.202402556
摘要
Abstract An alternative synthesis route to obtain ultramicroporous zeolitic imidazolate framework‐8 (ZIF‐8) is reported that is rapid and does not require organic solvent or heating. The polyethylene glycol‐templated ZIF‐8 nanoparticles (<50 nm size) exhibited a high BET (Brunauer, Emmett and Teller) surface area of 1853 m 2 /g, a total pore volume of 0.73 cm 3 /g, and 0.54 nm ultramicropores. A new approach is introduced here to better understand gas adsorption in porous metal organic frameworks (MOFs) that combines theoretical and experimental isotherm data obtained for five gases with statistical physics modelling. The multiscale analytical model reveals that the gas molecules, irrespective of their structure, adsorb in a mixed orientation at low temperature, and a parallel multi‐molecular orientation at higher temperature. The number of gas molecules adsorbed per site ranged from 0.83–2.2 while the number of adsorbent layers ranged between 1.4–5.6, depending on the gas and the temperature. The multilayer adsorption processes involved adsorption energies from 2.85 kJ/mol–9.77 kJ/mol for all gases, consistent with physisorption via van der Waals and London dispersion forces. The initial adsorption energies were higher and therefore stronger. A particularly high capacity for CO 2 of 1088 mg(CO 2 )/g at 298 K was observed while H 2 adsorption was only 9 mg(H 2 )/g. The other gases adsorbed at 145 mg/g–245 mg/g at 298 K. Thermodynamic functions that governed the adsorption process such as the internal energy, the enthalpy, and Gibbs free energy, are also reported, as well as the adsorption entropies, for the 5 gases.
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