Rational design of silicas with meso-macroporosity as supports for high-performance solid amine CO2 adsorbents

Study of rice husk ash derived MCM-41-type materials on pore expansion, Al incorporation, PEI impregnation, and CO2 adsorption

“…As seen in Fig. 10(a), within the time frame of 120 min, the adsorption capacity peaked at 75 o C, which was previously reported when using PEI-impregnated MCM-41-type adsorbents [27,30,33,73,74]. Although low temperatures are favorable thermodynamically, a high temperature facilitates the interaction of CO 2 with additional active sites because of the enhanced mass transfer rate.…”

“…After 150 min of exposure to pure CO 2 atmosphere at 75 o C, they achieved an adsorption capacity of 215 mg of CO 2 per gram of PEI using M41 impregnated with 50 wt% PEI, which was 24 times higher than M41 alone and twice that of pure PEI. Recently, Chen et al [30] used M41 impregnated with 50 wt% PEI to achieve an uptake of ~117 mg of CO 2 per gram of adsorbent on exposure to 30 mL min 1 of pure CO 2 .…”

Insights into the Critical Role of Abundant-Porosity Supports in Polyethylenimine Functionalization as Efficient and Stable CO2 Adsorbents

“…On the other hand, most studies have concentrated on designing pore structures using a specific support, rather than selecting rational support types, which would ignore the importance of support types. 34,36 Indeed, the differences in PEI impregnation, CO 2 adsorption performance, and the physical/ chemical stability caused by distinct porous support types might be more pronounced. After all, in addition to the structural parameters, the great variation in chemical characteristics may lead to more remarkable interactions.…”

“…In general, to improve amine dispersion and CO 2 internal diffusion, the supports with abundant pore structures are superior for impregnating polyamines, which have larger molecular sizes. Hence, numerous researchers are devoted to developing pore-expanding approaches or synthesizing complex macro-/mesoporous materials in recent years. ,, As an example, a novel MOF–polymer composite with a hierarchical porous structure and a high surface area, was prepared via high internal phase emulsion template polymerization of divinylbenzene and glycidyl methacrylate and the in situ generation of MOF, and after PEI functionalization, the highest adsorption capacity could reach 4.3 mmol/g . It is worth noting that the complex approach to synthesize porous supports will dramatically reduce the scalability and cost-effectiveness, which are originally the prominent advantages of the impregnation method, and possibly use various environmental-unfriendly organic agents.…”

“…On the contrary, some commercial abundant-porosity supports can also achieve excellent CO 2 adsorption performance and stability, and more importantly, the available materials will be favorable for developing practical applications of amine-functionalized adsorbents. On the other hand, most studies have concentrated on designing pore structures using a specific support, rather than selecting rational support types, which would ignore the importance of support types. , Indeed, the differences in PEI impregnation, CO 2 adsorption performance, and the physical/chemical stability caused by distinct porous support types might be more pronounced. After all, in addition to the structural parameters, the great variation in chemical characteristics may lead to more remarkable interactions.…”