A study on the effect of the amine structure in CO2 dry sorbents on CO2 capture

• In situ polymerization of aminosilane inside SiO2 increased amine content and amine surface density was improved significantly.
• This eventually resulted to enhance adsorption capacity.
• The temperature range at which the adsorbed species started to be desorbed varied depending on amine type.
• Silylpropylcarbamate and carbamic acid were the mostly desorbed species at the lower desorption temperature range of below 70 °C.
• Carbamate mostly desorbed at higher desorption temperature above 90 °C.

Carbon dioxide capture and sequestration (CCS) has received considerable attention as total energy dependency on fossil fuel continues to increase. One of the crucial technologies of CCS is the development of organic–inorganic hybrid dry sorbent for CO2 capture in adsorption processes. In this study, in situ polymerization and functionalization technology of aminosilane inside the pore of silica was employed to prepare a sorbent with enhanced characteristics. It was confirmed that the sorbent prepared through in situ polymerization of aminosilane inside the pore of SiO2 showed higher amine content and enhanced CO2 adsorption capacity than the sorbent prepared by conventional grafting method. Furthermore, the polyaminosilane functionalized sorbent was evaluated by in situ IR to examine the CO2 adsorption and desorption behaviors and species during the temperature swing process. The CO2-adsorbed species were found out to be silylpropylcarbamate, carbamic acid and carbamate. Though the similar adsorbed species were observed regardless of amine structure of the aminosilane incorporated, the desorption temperatures of the each adsorbed species were strongly affected by the amine structure. Consideration of these desorption behaviors can be beneficial in the selection of the desorption condition upon implementation of these sorbents in commercial capturing process.

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