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Doping The Polarizability Of The Gas Bonds ( HKUST )

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It was also due to the increase in the polarizability of the organic cage which strengthens the framework through van der Waals and charge-quadrupole interaction with the gas molecule [75]. Yang and coworkers [76] also synthesized the Li-doped HKUST-1/MWCNT composite through a post-synthesis route by doping the Li cations into the parent HKUST-1 MOF/CNTs. The gas uptake per effective specific surface area of doped material increased ca. 305% for CO2 compared to the unmodified HKUST-1 at 298 K and 18 bar. Alternatively to MOFs, a similar situation has been observed when Lan et al. [76] demonstrated the effect of doped metals (Li, Na, K, Be, Mg, Ca, Sc and Ti) into the COFs for CO2 adsorption and the result shows that Li+ a secondary atom is …show more content…

When CO2 interacts, a charge polarization mechanism takes places in which a metal ion polarizes the nearby CO2 molecule and a weak van der Waals’ interaction formed between the CO2 molecule and MOF-5. Furthermore, the bonding between the metal ion and CO2 molecule at this site also might be through a simple dispersion and electrostatic interaction [76x].
For particle application, MOFs should not only possess high surface area and pore volume but also thermally and chemically stable for CO2 adsorption. Many MOFs are air and/or moister sensitive following the evacuation of the pores and need careful handling under an inert atmosphere to obtain require best performance characteristic. However, one of the key factors in the CO2 adsorption within the MOFs is the moister because water and carbon dioxide are both polar molecules and same attributes makes MOFs attractive candidate. Certainly, water can directly can compete CO2 gas molecule for active sites within MOFs and can form a hydrate at suitable temperature and pressure, therefore, drastically decrease the overall CO2 adsorption capacity. For an application such as post-combustion CO2 adsorption, where a substantial amount of water is present in the gas stream, an increased chemical stability will be a curial factor if MOF is to be

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