Mesoporous silica supported amine and amine-copper complex for CO2 adsorption: Detailed reaction mechanism of hydrophilic character and CO2 retention

Mesoporous silica SBA-15 was functionalized with various amines and then doped with copper II cation (Cu2+). The modified materials were tested for the retention of CO2 at room temperature using temperature-programmed desorption (CO2-TPD). Several parameters affecting the CO(2 )retention capacity (CRC) such as the nature of amine groups, repetitive adsorption-desorption cycles and dispersion of copper were investigated. CO2-TPD and H2O-TPD allowed correlating the hydrophilic character with the CO2 retention capacity. The obtained results showed that amine-functionalized mesoporous materials containing their own moisture exhibit higher effectiveness in the retention of CO2. Triamine-functionalized SBA-15 displayed the highest CRC value as a result of the increase of the number of adsorption sites. Material reuse in three adsorption/desorption cycles revealed high stability with a slight decrease in CRC. The dispersion of copper induced a progressive decrease in the CRC value. The CRC decreased with increasing Cu(2+ )content due to competitive complexation of Cu2+ by the amino groups. (C) 2019 Elsevier B.V. All rights reserved.