Experimental and computational investigation of CO2 capture on amine grafted metal-organic framework NH2-MIL-101

A standard metal-organic framework, NH2-MIL-101 based on chromium has been synthesized. For the purpose of offering more binding sites for CO2, post-synthetic modification of tetraethylenepentamine (TEPA) was conducted by using a wet impregnation method. With the aim of better understanding the thermodynamics and mechanisms of CO2 adsorption, molecular dynamics (MD) simulations have been used for structures optimization and adsorption kinetics of NH2-MIL-101/TEPA adsorbents, and the CO2 adsorption capacity with different TEPA loadings was simulated by the Monte Carlo (MC) method. Results confirmed that TEPA was successfully grafted on the coordinative unsaturated metal centers. At 1 bar and 298 K, NH2-MIL-101 combined with 50 wt% TEPA exhibited a CO2 uptake of 3.1 mmol/g-sorb. Under low loading of TEPA, the coordinative unsaturated metal centers made a relatively big contribution to CO2 adsorption. With more TEPA incorporated, the CO2 binding affinity was enhanced due to the existence of abundant amine groups. On the basis of both experimental and simulation analysis, this synthesized amine-grafted sorbent with excellent CO2 capture performance is an ideal material for greenhouse gas control. (C) 2016 Elsevier B.V. All rights reserved.