Efficient carbon dioxide adsorption properties of cellular structure Li4SiO4 sorbents prepared by additive manufacturing based on polymer-derived ceramics strategy

Li 4 SiO 4 is considered as one of the most promising materials for post-combustion CO 2 capture at high temperature due to its inherent merits. To avoid elutriation in practical application, granulating and shaping of Li 4 SiO 4 sorbents are getting extensive attention. However, the cylindrical or spherical pellets prepared by traditional methods are prone to result in severe damping of CO 2 capture performance. In this work, the cellular structure Li 4 SiO 4 sorbent was firstly yielded by additive manufacturing based on polymer-derived ceramics strategy. The phase evolution and calcination process were investigated to optimize the microstructure of that sorbents. In addition, three sodium halides were severally doping in Li 4 SiO 4 sorbents to further improve the CO 2 uptake, and the enhancement mechanism was studied. Results show that abundant gas channels around the Li 4 SiO 4 grain can be generated by a novel residual carbon controlling calcination. Additionally, the 6 mol% NaF doped cellular structure Li 4 SiO 4 sorbents possessed superior CO 2 adsorption capacity: 0.329 g CO2 /g sorbent in 70 vol% CO 2 and 0.286 g CO2 /g sorbent in 15 vol% CO 2 , as well as ultrafast adsorption rate. Especially, the sorbents still kept a high adsorption capacity of 0.274 g CO2 /g sorbent and obtained a more efficient regeneration process after undergoing 15 cycles of adsorption–desorption in a low CO 2 concentration flue gas. Hence, the introduction of additive manufacturing and polymer-derived ceramics strategy in fabrication of Li 4 SiO 4 sorbents provides a new approach and promising prospects for the high-temperature CO 2 capture.