Facile, time-saving cigarette butt-assisted combustion synthesis of modified CaO-based sorbents for high-temperature CO2 capture

Abstract

Highly efficient and stable Zr-incorporated CaO-based sorbents were synthesized using a facile, cigarette butt-assisted combustion synthesis (CAC) method. Comparative investigation of CAC method with two common synthesis methods (i.e., wet-mixing, sol–gel) on producing CaO-based sorbents was conducted. The sorbents synthesized by the CAC and sol–gel methods exhibit superior cyclic CO2 capture capability compared to wet-mixing. More importantly, the CAC belongs to impregnated layer solution combustion synthesis and takes markedly shorter time compared to sol–gel, possessing the potential of scaled-up preparation. The optimization of combustion temperature and incorporation ratio of Zr-based support on synthesis of CaO-based sorbents by CAC method was further conducted. The proper combustion temperature selected to synthesize Zr-incorporated CaO-based sorbents using CAC method is 750 °C. Too high or low combustion temperature may result in unsatisfactory pore structure of synthetic CaO-based sorbents because of excessive sintering or generating in-situ CaCO3, respectively. The synthetic CaO-based sorbents with 25 wt% of ZrO2 exhibit the outstanding CO2 capture performance (CaO carbonation conversion of 63.8% after 17 cycles) due to the generation of extensive CaZrO3 grains acting as the inert skeleton. Additionally, the combination of cigarette butt-assisted combustion and graphite-moulding can prepare Zr-incorporated CaO-based pellets with desirable practicality.