CO<sub>2</sub> Adsorption on a CaO–Ca<sub>12</sub>Al<sub>14</sub>O<sub>33</sub> Composite Synthesized from a Blast Furnace Slag and its Regenerative Ability

Utilizing a reversible reaction between CaO and CO2, namely the calcium looping (CaL) process, is among CO2 adsorption sequestration techniques that have been intensively studied over years. While CaO-based sorbents offer numerous advantages, such as broad accessibility, low cost, relatively high theoretical uptake (0.78 gram of per CaO), its capture capability during cyclic operation degrades substantially, which has remained an important issue for commercial CaL process applications. To address aforementioned problem, in this study, we synthesized CaO–Ca12Al14O33 (BFS-CaO-CAO) composite from blast furnace slag (BFS) by using two types inorganic acid, nitric hydrochloric acid. Acid-leaching subsequent separation SiO2 content BFS resulted formation Ca–Al-based layered double hydroxide, was then transformed into mixed oxide Ca12Al14O33 via thermal decomposition. According to TGA adsorbent produced with acid (BFS-CaO-CAO(NO3)) had better (13 wt% mass adsorbent) regenerative ability compared analog (BFS-CaO-CAO(Cl)). Moreover, presence mayenite (Ca12Al14O33) adsorbent, acted inert binder, effectively prevented sintering agglomeration particles. A low-cost, ecologically viable CO2-adsorbent advantageous lowering emissions.