A Bio‐Metal–Organic Framework for Highly Selective CO₂ Capture: A Molecular Simulation Study

Abstract

A recently synthesized bio-metal-organic framework (bio-MOF-11) is investigated for CO(2) capture by molecular simulation. The adenine biomolecular linkers in bio-MOF-11 contain Lewis basic amino and pyrimidine groups as the preferential adsorption sites. The simulated and experimental adsorption isotherms of pure CO(2), H(2), and N(2) are in perfect agreement. Bio-MOF-11 exhibits larger adsorption capacities compared to numerous zeolites, activated carbons, and MOFs, which is attributed to the presence of multiple Lewis basic sites and nano-sized channels. The results for the adsorption of CO(2)/H(2) and CO(2)/N(2) mixtures in bio-MOF-11 show that CO(2) is more dominantly adsorbed than H(2) and N(2). With increasing pressure, the selectivity of CO(2)/H(2) initially increases owing to the strong interactions between CO(2) and the framework, and then decreases as a consequence of the entropy effect. However, the selectivity of CO(2)/N(2) monotonically increases with increasing pressure and finally reaches a constant. The selectivities in bio-MOF-11 are higher than in many nanoporous materials. The simulation results also reveal that a small amount of H(2)O has a negligible effect on the separation of CO(2)/H(2) and CO(2)/N(2) mixtures. The simulation study provides quantitative microscopic insight into the adsorption mechanism in bio-MOF-11 and suggests that bio-MOF-11 may be interesting for pre- and post-combustion CO(2) capture.

Computational Modeling of bio-MOFs for CO2/CH4 separations

“…However, the number of computational studies on bio-MOFs is very limited in the literature. Chen and Jiang (Chen and Jiang, 2010) investigated separation performance of bio-MOF-11 for CO 2 /N 2 and CO 2 /H 2 mixtures using molecular simulations. The high adsorption selectivity (375) computed for CO 2 /H 2 mixture at 298 K at 4 bar was attributed to the presence of Lewis-basic sites in adenine which improves the interactions with CO 2 molecules.…”

CO2 capture in cation-exchanged metal–organic frameworks: Holistic modeling from molecular simulation to process optimization

“…The dispersive interactions of framework atoms and cations were modeled by the Universal Force Field (UFF) (Rappe et al, 1992), as listed in Table 1. A number of simulation studies have shown that UFF can accurately predict gas adsorption in various MOFs (Babarao and Jiang, 2008;Chen and Jiang, 2010;Skoulidias and Sholl, 2005;Garberoglio et al, 2005). CO 2 was modeled by a three-site rigid molecule, in which the partial charges on C and O atoms were q C ¼0.576e and q O ¼ -0.288e (e¼1.6022 Â 10 -19 ) (Hirotani et al, 1997).…”

Molecular Simulation Studies of Flue Gas Purification by Bio-MOF

“…In the past decades, a number of methods have been proposed to solve the problem including cryogenic distillation, amine scrubbing, and sorbent adsorption [1]. Among these methods, pressure swing adsorption (PSA) technology and membrane separation based on porous materials are known to be efficient and affordable processes for CO2 removal from flue streams.…”