Tunable amine loading of amine grafted mesoporous silica grafted at room temperature: Applications for CO₂ capture

SBA-15 was employed to study amine-grafting in dry and wet grafting conditions at low temperature. SBA-15 was amine-grafted at 30 °C and for contrast SBA-15 was conventionally grafted at 85 °C to determine how amine-grafting at 30 °C affects amine-grafting outcomes. It was found that under dry grafting conditions, adsorbents grafted at 30 and 85 °C exhibited similar amine loadings. It was also found that when water was added during grafting, adsorbents grafted at 30 °C displayed higher amine loadings than those at 85 °C. At 30 °C, more water can occupy the pore space of the SBA-15 prior to clogging of the pores, resulting in higher amine loading. This results in higher CO₂ capacities at 75 °C for adsorbents grafted at 30 °C. The stability of materials grafted at 30 °C and the universality of the studied effects for other aminosilanes and mesoporous silica supports were demonstrated.