Flame-Made Durable Doped-CaO Nanosorbents for CO2 Capture

The present study deals with the design and development of novel calcium-oxide-based refractory sorbents synthesized by flame spray pyrolysis (FSP) for carbon dioxide capture. The FSP-derived sorbents inherently exhibit very large CO2 uptake capacity in the present investigation. Sorbents derived from conventional wet chemistry, possessing identical composition, were synthesized and evaluated. A wide range of refractory dopants, (Si, Ti, Cr, Co, Zr, and Cc) were employed, aiming at developing sorbents with good mechanical strength. Among all of the doped CaO sorbents, Zr-doped CaO was found to exhibit the best CO2-capture performance under identical conditions of operation. To study the effect of Zr in depth and find out the optimal concentration of Zr needed in the CaO matrix, a series of Zr-incorporated CaO sorbents were synthesized by varying the relative composition of Zr in the CaO base matrix. The present studies suggest that Zr/Ca in the 3: 10 atomic ratio results in the formation of the most robust nanosorbent for multicyclic operation. This sorbent retained, unchanged, its ability to capture CO2 during extended cycles. It also demonstrated excellent stability under operating in the presence of water vapor (10 vol %). The present paper represents two novel developments in the field Of CO2 capture, first, the superiority of FSP process and, second, the role of ZrO2 dopant in improving the durability and robustness of the CaO-based sorbent.