Amine-Grafted MIL-101(Cr) for Superior CO2 Capture: Performance, Kinetics, and Thermodynamics

Carbon dioxide capture is critical for mitigating climate change. Amine-functionalized MIL-101(Cr) shows great promise due to its high stability and tunable porosity. We optimized its synthesis (160°C, 24 h, 150°C activation) and investigated diethylenetriamine (DETA) loading effects. The 50 wt% DETA composite achieved a CO 2 uptake of 1.25 mmol/g at 30°C and 0.1 bar, nearly six times that of pristine MIL-101(Cr). Kinetic and isotherm data were well described by the pseudo-second-order and Langmuir models. Thermodynamic analysis revealed Δ H = −54.78 kJ/mol and Δ S = −142.13 J/(mol K), confirming an exothermic, chemisorption-dominated process. We further optimized adsorption/desorption conditions, identifying optimal working temperatures of 269.47 K (adsorption) and 388.20 K (desorption). This work provides clear guidance for designing high-performance metal–organic framework (MOF)-based CO 2 capture materials.