CO2 Adsorption Behavior and Kinetics on Amine-Functionalized Composites Silica with Trimodal Nanoporous Structure

A trimodal porous support with special trimodal pore structure has been prepared by physically mixing the silica gel (HPS) and SBA-15 and then devoted to fabricate TEPA-functionalized adsorbent for CO2 capture. The trimodal multistage mesopores structure can promote the TEPA dispersion and mitigate the mass-transfer resistance in the adsorbent and, hence, improve capture performance, compared to the single mesoporous support. The influence of the mass ratios of HPS to SBA-15, amine loaded amount, CO2 concentration, adsorption temperatures, and water vapor were studied. The CO2-saturated adsorption amount of 5.05 mmol/g was obtained at 75 °C in dry N2 flow containing 15 vol % CO2 when the mass ratio of SBA-15 to HPS was 1:2 with 50 wt % TEPA loadings. Moreover, the CO2-saturated adsorption amount presented a 16% improvement in humid N2 flow containing 15 vol % CO2 flow at 75 °C. In addition, the S2HPS-TEPA50% also demonstrated good stability after 10 adsorption/desorption cycles. Based on in situ DRIFTS re...