(4bp) Nanocomposite Sorbents for High Efficiency CO2 Capture

Carbon dioxide has drawn significant attention for being one of the main anthropogenic contributors to climate change. Various approaches, such as solvents, membranes and solid sorbents, have been proposed to capture CO2 using. Among those, liquid amine scrubbing is the most widely studied technology for CO2 capture on industrial scale. Although effective at CO2 capture, amine scrubbing has a number of shortcomings including the corrosive nature, energy intensive regeneration process, and solvent degradation via oxidation and vaporization. In contrast to the liquid amine scrubbing technique, solid-supported amine sorbents offer significant advantages for CO2 capture, such as low energy requirement for sorbent regeneration, and potential elimination of corrosion problems. Meanwhile, solid-supported amine sorbents exhibit high selectivity and reversibility for CO2 capture due to the CO2-amine chemistry. Because of the numerous advantages, a great deal of effort has been directed towards the development of solid-supported amine sorbents for CO2 capture. However, the application of solid-supported amine sorbents is largely limited by their relatively low CO2 capture capacity. High capture efficiency sorbents with good recyclability are required in order to develop an economically feasible industrial-scale process. Here robust nanocomposite sorbents for high efficiency CO2 capture have been developed based on specially designed mesoporous silica impregnated with polyethylenimine (PEI). The newly synthesized composite sorbents exhibit extraordinary capture capacity up to 7.9 mmol of CO2 /g of sorbent under simulated flue gas conditions. The sorbents have fast CO2 capture kinetics and reach their 90% of the total capacities within few minutes. Other than the high capacity and fast sorption kinetics, the sorbents also show full reversibility and good stability during cyclic adsorption-regeneration tests. The new sorbents reported here offer many advantages over the amine scrubbing technique and show promise as a potential candidate for alternative CO2 capture technologies.