In-situ grafted amine functionalized metal-organic frameworks for CO2 capture: Preparation and bench-scale performance evaluation
Srikanta Dinda
Abstract
The work includes the preparation of zirconium fumarate (ZrFu) metal-organic framework (MOF) and investigation of the CO 2 capture performance of the material. The CO 2 adsorption experiments were performed in a bench-scale flow reactor with a simulated flue gas mixture . To enhance the CO 2 capture capacity of the ZrFu material, two polydentate amines, namely diethylenetriamine (DETA) and tetraethylenepentamine (TEPA) were incorporated into the ZrFu by an in-situ grafting method. The effects of adsorption temperature, pressure, amine loading, and CO 2 concentration in the feed gas mixture on CO 2 capture were examined. The obtained value of the CO 2 uptake capacity of the pristine ZrFu is 73 g CO 2 /kg sorbent at 30 ºC under atmospheric pressure. Among the amine-modified MOFs, the DETA-modified ZrFu (10-DETA-ZrFu) showed a maximum adsorption capacity of 86 g CO 2 /kg sorbent. It is also noted that at 90 °C, the CO 2 adsorption capacity of the material is 57 g CO 2 /kg sorbent, which is about 67% of the capture capacity at 30 °C. This demonstrates that the MOFs can capture and retain the CO 2 molecules inside the MOF moiety even at higher temperatures. The study also revealed that the synthesized MOFs are chemically stable with about 10% moisture environment. The prepared MOFs exhibited admirable thermo-chemical stability up to around 150 °C. Among the studied isotherm models, the Langmuir model showed a good agreement with the experimental data for lower values of adsorption pressure. The estimated value of adsorption energy for the adsorption of CO 2 on ZrFu is 6.9 kJ/mol at 30 °C.