Industrial solid waste-based sorbents for high-temperature CO2 capture and conversion

In this work, a “CO 2 capture and ex situ utilization” strategy was proposed by combining calcium looping and a subsequent cycloaddition reaction. In the calcium looping step, the CaO-based sorbent was prepared from bulk industrial solid waste, i.e., carbide slag as the calcium source and blast-furnace slag as the dopant. Both wet mixing and sol-gel methods were explored in this study. Among them, the sorbent synthesized via the sol-gel route with sucrose as a complexing agent showed improved cyclic performance. This improvement is presumably attributable to the sol-gel method's ability to enhance the distribution of blast furnace slag and optimize the sorbent's pore structure. By further regulating sorbent preparation parameters such as the mass ratio of carbide slag to blast furnace slag, the sucrose amount, and the calcination temperature and time, the optimal sorbent was obtained with an initial CO 2 uptake of 0.552 g CO 2 /g sorbent at 740 o C. Furthermore, the CO 2 uptake was still retained at 92% even after 10 cycles. The CO 2 released from Ca-looping ex situ reacted with propylene oxide (PO) to afford a 91% yield of propylene carbonate catalyzed by graphene oxide (GO) and tetrabutylammonium bromide (TBAB), avoiding conventional CO 2 compression and transportation. As expected, this study represents a potential large-scale application of integrating industrial solid waste management, carbon capture, and valorization to value-added chemicals and materials.