resumo
Here, we report the preferential CO2 adsorption on a new zinc-based porous 3D framework compound, [Zn-2(H2O)(nic)(pyrz)](n)center dot nH(2)O, which has solvent accessible void space. Upon dehydration the porosity of the framework compound was enhanced significantly. At 298 K, the as-synthesized and dehydrated compound showed an uptake of carbon-dioxide of 2.2 and 5.7 wt% at 0.15 bar and 5.3 and 12.2 wt% at 1 bar, respectively, which increased to 5.6 and 11.7 wt% at 0.15 bar and 10.2 and 23.6 wt% at 1 bar, respectively, upon cooling to 273 K. The selectivity of CO2 with respect to CH4 at 273 K is calculated to be 22.4. The framework compound and its dehydrated product show very selective CO2 adsorption with respect to other small gas molecules like H-2, N-2, and CH4 at low partial pressure. The low pressure selective CO2 adsorption is quite impressive with respect to other reported framework systems where selectivity was found particularly over one or two small gas molecules amongst H-2, N-2, and CH(4)etc. [Zn-2(H2O)(nic)(pyrz)](n)center dot nH(2)O exhibits fairly strong CO2-framework interactions as evidenced from the measured heat of adsorption, similar to 50 kJ mol(-1) at low loading. Molecular dynamics and Monte Carlo simulations explain the selective CO2 adsorption over other small gas molecules (H-2, N-2 and CH4) in the framework compound.
palavras-chave
METAL-ORGANIC FRAMEWORKS; SELECTIVE GAS-ADSORPTION; COORDINATION POLYMERS; PORE-SIZE; HYDROGEN ADSORPTION; SORPTION PROPERTIES; FUNCTIONAL-GROUPS; CAPTURE; SITES; SURFACE
categoria
Chemistry
autores
Saha, D; Gayen, S; Maity, T; Frontera, A; Ortega-Castro, J; Leus, K; Wang, GB; Van Der Voort, P; Brandao, P; Koner, S
nossos autores
Paula Cristina Ferreira da Silva Brandão
Investigador Auxiliaragradecimentos
Financial assistance received from UGC through a project (to S. K.) is gratefully acknowledged. D. Saha acknowledges University Grants Commission, New Delhi, India for financial assistance (Minor Research Project No. F. PSW-188/15-16 (ERO)). S. Gayen is thankful to the University Grants Commission (UGC), New Delhi (Award letter no. 22/12/2013(ii)EU-V) through a national eligibility test (NET) fellowship. Financial assistance received from the European Commission for a short term research stay of S. Koner at Ghent University is gratefully acknowledged. We also thank Dr Himanshu for his help in the IAST calculation.