Amine-Functionalized Metal Organic Framework as a Highly Selective Adsorbent for CO₂ over CO

An amine-functionalized metal organic framework, TEPA-MIL-101, was prepared by grafting tetraethylenepentamine (TEPA) on the coordinatively unsaturated Cr­(III) sites of MIL-101 for the selective adsorption of CO₂ over CO. The adsorbents were characterized using various techniques. The results indicate that the TEPA molecule was successfully grafted on Cr­(III) without destroying the intrinsic structure of MIL-101. Isotherms for CO₂ and CO adsorption on MIL-101 and TEPA-MIL-101 were obtained to determine the effects of the grafted TEPA on the CO₂ adsorption capacity and selectivity. The results show that the CO₂ capacity on TEPA-MIL-101 was higher than that on MIL-101 at lower pressures, whereas the CO capacity sharply decreased. The selectivity for CO₂ over CO was clearly improved from 1.77 to 70.2 at 298 K and total pressure 40 kPa. The density functional theory calculation for the adsorption of CO₂ and CO on TEPA indicates that the bonding energy of CO₂ is obviously higher than that of CO. Analysis of the cyclic adsorption performance reveals the high stability of the adsorbent. On the basis of the experimental and simulation results, the grafting of amines on coordinatively unsaturated sites of metal organic frameworks is an effective method of achieving selective adsorption of CO₂ over CO

Modified Stern-Volmer plots of SaB-BSA system andHYSA-BSA system.

<p>Modified Stern-Volmer plots of SaB-BSA system andHYSA-BSA system.</p

Fluorescence studies of the SaB-BSA system coexisting with other components in SFDHI.

<p>Fluorescence studies of the SaB-BSA system coexisting with other components in SFDHI.</p

The calculated fluorescence parameters of single tested component with BSA, at 310 K and pH 7.2.

<p>The calculated fluorescence parameters of single tested component with BSA, at 310 K and pH 7.2.</p

Binding parameters of SaB-BSA system in the absence and presence of SFDHI, at 310 K, pH 7.2.

<p>K’_b is the K_b of SaB-BSA system in the presence of coexisted components.</p><p>Binding parameters of SaB-BSA system in the absence and presence of SFDHI, at 310 K, pH 7.2.</p

Docking scores for all of the natural components in DHI binding to BSA and HSA.

<p>Docking scores for all of the natural components in DHI binding to BSA and HSA.</p

Results for Site marker competitive experiments.

<p>Results for Site marker competitive experiments.</p

Chemical structures of HSAand BSA.

<p>Chemical structures of HSAand BSA.</p

Binding parameters of competitive experiments of SaB-BSA system, at 310 K, pH 7.2.

<p>Binding parameters of competitive experiments of SaB-BSA system, at 310 K, pH 7.2.</p

Docking orienations of SaB for binding on BSAand HSA.

<p>Docking orienations of SaB for binding on BSAand HSA.</p