Direct Air Capture of CO2 Using Amine Functionalized MIL 101(Cr)
Direct adsorption of CO2 from ambient air, also known as direct air capture (DAC) is gaining attention as a complementary approach to processes that capture CO2 from more concentrated sources such as flue gas. Oxide supported amine materials are effective materials for CO2 capture from dilute gases, but less work has been done on metal organic framework (MOF) supported amine materials. Use of MOFs as supports for amines could be a versatile approach to the creation of effective amine adsorbents because of the tunability of MOF structures. In the present work, MIL 101(Cr) materials functionalized with amine species are evaluated for CO2 capture from simulated air. Two amines are loaded into the MOF pores, tris (2 amino ethyl) (TREN) and low molecular weight, branched poly(ethylene imine) (PEI 800) at different amine loadings. The MIL 101(Cr) TREN composites showed high CO2 capacities for high loadings of TREN, but a significant loss of amines is observed over multicycle temperature swing adsorption exper.