Reinforced CO₂Capture on Amine-Impregnated Organosilica with Double Brush-like Additives Modified

Additive introduction based on porous amine-silica hybrid materials is one of the key technologies to enhance the ability of CO2 capture. Hence, we first developed a one-step strategy of directly introducing brush-like cetyltrimethylammonium chloride (CTAC) and bis-(γ-triethoxysilylpropyl)-tetrasulfide (BTES) additives into the silica support to prepare micro-mesoporous organosilica nanoparticles with double brush-like additives modified (MMON-D). Then, the amine-functionalized CO2 adsorbent (MMON-D-50) was obtained via tetraethylenepentamine impregnation. The adsorbent with double additives exhibited a higher CO2 adsorption performance (4.04 mmol/gadsorbent and 0.33 mmol CO2/mmol N under pure CO2 and 25 °C conditions) than that of the adsorbents with none or a single additive. Furthermore, spectra analysis, kinetics, and adsorption heats were performed to clarify the adsorption mechanism of the synergistic action of CTAC and BTES. The results revealed that CTAC as a quaternary ammonium formed on the adsorbent surface can facilitate the formation of carbamic acid. Meanwhile, BTES as a swelling agent endows silica support with a large pore size and inhibits the formation of silylpropyl carbamate to enhance CO2 adsorption performance. This work supplies a novel surface-modified strategy for developing adsorbents with excellent CO2 capture performance, which is of prime importance for both academic interests and practical applications.