Computational Study on Metal-Ion-Decorated Prismane Molecules for Selective Adsorption of CO₂ from Flue Gas Mixtures

Abstract

Selective adsorption of CO 2 from flue gas is extremely significant because of its increasing concentration in air and its deleterious effect on the environment. In this work, we have explored metal-ion-bound prismane molecules for selective CO 2 adsorption from the flue gas mixture. The Ca 2+ -bound prismane complex exhibits superior CO 2 selectivity and adsorption capacity. The calculated binding energy and molecular electrostatic potential (MESP) analysis showed that the rectangular face of prismane binds strongly with metal ions as compared to its triangular face. The CBS-QB3 and density functional theory-based functional M06-2X/6-311+G(d) calculations show that the prismane molecule can bind to one Li + , K + , Mg 2+ , and Ca 2+ ion with favorable binding energy. The metal-ion-bound prismane complexes have been examined for their CO 2 , N 2 , and CH 4 adsorption capacity. Prismane−Ca 2+ can bind with six CO 2 molecules strongly with an average binding energy of −18.1 kcal/mole as compared to six N 2 (−12.6) and five CH 4 (−13.4) gas molecules. The gravimetric density calculated for the CO 2 -adsorbed prismane−Ca 2+ complex has been found to be 69.1 wt %. The discrete hydrocarbon structure for selective separation of CO 2 is rare in the literature and can have potential applications for cost-effective CO 2 capture from the flue gas mixture.

Anin silicostudy of the selective adsorption and separation of CO2from a flue gas mixture (CH4, CO2, N2) by ZnLi5+clusters

“…38 Similarly, CH 4 and N 2 show better gravimetric density as compared to MOFs and reported alkali-doped prismane complexes. 38,60…”

“…In the case of CO 2 , the gravimetric density reaches 75.26 wt%, which is closer to previously reported systems such as metal-organic-framework, 60 Si-B-N sheets, 61 and metal-doped prismane system. 38 Similarly, CH 4 and N 2 show better gravimetric density as compared to MOFs and reported alkali-doped prismane complexes. 38,60 Further, the binding energy has been decomposed into physically meaningful components such as exchange, induction, electrostatic, and dispersion.…”

“…38 Similarly, CH 4 and N 2 show better gravimetric density as compared to MOFs and reported alkali-doped prismane complexes. 38,60 Further, the binding energy has been decomposed into physically meaningful components such as exchange, induction, electrostatic, and dispersion. Numerical values of different energies are provided in Table S2 (ESI †).…”

“…In 2014, Wang et al characterized a boron-based transition metal-centered wheel-like anionic cluster for CO 2 separation from a flue gas mixture. 38 The interaction energy of their anionic cluster with CO 2 was greater compared to N 2 and CH 4 , which is essential for CO 2 separation. In 2020, Wakchaure and Ganguly explored metal–ion-bound prismane molecules for the selective adsorption of CO 2 from a flue gas mixture.…”

“…Further, some modifications such as the doping of nitrogen, some alkali and alkaline earth metal cations (Li + , K + , Mg 2+ , Ca 2+ ) as well as transition metals (Sc, Ti, V, Cr, Mn, Fe, Co) enhanced the adsorption capability of CO 2 on the MOFs, carbon-based structure, silicates, etc. [31][32][33][34][35][36][37][38][39] Few demerits were also found with the carbonbased structure like deformation with increasing temperature, poor pore size for proper CO 2 separation especially for carbon porous materials, etc. [40][41][42][43] To overcome these limitations, such as its stability, durability, and selectivity, we need to find some way to improve the interaction of CO 2 with the adduct, which will lead to effective separation from other gases in a mixture of flue gas.…”