Monoamine-grafted MCM-48: An efficient material for CO2 removal at low partial pressures

Mesoporous cubic MCM-48 material was synthesized and functionalized with 3-aminopropyltriethoxy-silane (APTES) under different conditions and used for CO2 adsorption. Before and after functionalization the materials were characterized by different techniques: XRD, TEM, TGA, fluorescence analysis of amino and adsorption–desorption isotherms of N2 and CO2. The results confirmed that CO2 adsorption in amino modified materials involves both chemisorption and physisorption. The former is the primary mechanism at low partial pressures, and includes the formation of carbamates. This material demonstrated a high efficiency for CO2 removal at low CO2 partial pressures, with loadings of 0.5 mmolCO2/molN at 5 kPa. The maximum adsorption capacity at 1 atm of CO2 was 1.68 mmol/g.

► Total coverage surface and accessibility required for maximum adsorption efficiency.
► Mild conditions for amine functionalization of MCM-48 to avoid structure collapse.
► Maximum adsorption at 5 kPa CO2 equals 1.09 mmol CO2/g.