Insight into the application of amino acid-functionalized MIL-101(Cr) micro fluids for high-efficiency CO2 absorption: Effect of amine number and surface area

Abstract

Today, the combination of liquid absorbents and different additives like nano/micro particles (NPs, MPs) and amines for carbon dioxide (CO2) absorption has significantly increased. In this work, as a new approach, by considering the outstanding benefits of metal organic framework (MOF) structures, MIL-101(Cr)-CH2-Glycine (MIL-101(Cr)-Glycine), MIL-101(Cr)-CH2-Histidine (MIL-101(Cr)-Histidine) and MIL-101(Cr)-CH2-Arginine (MIL-101(Cr)-Arginine) with different amine numbers (1 to 4) are synthesized and subsequently, employed as an additive for the CO2 absorption improvement of pure water in a batch mode. To evaluate the efficiency of the applied MOFs, the impact of varying operating parameters including pressure, MOF concentration, MOF stability in the liquid phase and amine number are examined. According to the obtained results, applying all amino acid-functionalized MOFs causes a better performance in CO2 absorption compared to bare MIL-101 due to chemical reactions of amino groups with CO2 and formation of carbamate during the absorption experiment. Ultimately, MIL-101(Cr)-Arginine micro fluid results in the highest CO2 absorption enhancement because of its four amine number and raises the CO2 absorption up to 39% compared to pure water as a base fluid.