It is noted that the amount of CO2, as the cost of energy and resource consumption, showed a dramatic upward trend during recent decades. This has upset the ecosystem and increased the burden on the environment, and thus facilitates the development of CO2 capture technology in industry. Calcium-looping technology for CO2 capture in high temperature plays a key role in future prospects of sustainable development. Aiming to the limitation of rate and capacity of cyclic CO2 uptake caused by deactivation of Ca-based sorbents, we proposed an inexpensive, environment-friendly and widely applicable strategy to synthesize Ca-based sorbents through wet-mixing of various calcium precursors and fumed nano-SiO2. Actually, the as-synthesized sorbents from several calcium precursors, which are all easily available and low-cost, were tested by thermal gravimetric analyzer under both mild and severe conditions of carbonation and calcination. Consequently, among these calcium precursors, the calcium acetate showed the best performance for its initial CO2 uptake of 0.45 g(CO2) g(CaO)-1 and kept a relatively high CO2 uptake of 0.32 g(CO2) g(CaO)-1 after 30 cycles. Furthermore, compared with synthesized sorbents via physically dry-mixing, wet-mixing procedure possessed higher CO2 uptakes separately due to the more uniform separation. To some extent, the high cyclic CO2 uptakes were attributed to the stable larnite (CaSiO4), formed by the reaction of calcium precursors and fumed nano-SiO2. Additionally, SEM, TEM and N2 physisorption techniques have offered good proofs for the research of the stable mechanism throughout whole cycles. The improvement on cyclic CO2 uptakes and the investigation of various calcium precursors with fumed nano-SiO2 should be benefit for the application of calcium looping in the future industrial project.

Green synthesis of stable nano-SiO2/CaO composites for fast CO2 capture

2019 Fall National Meeting

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