CO ₂ adsorption and desorption behavior on ternary CaO-AC-TiO ₂ composites prepared by mechanical milling

CO2 adsorption and desorption were studied on novel ternary composites with different weight percentage ratios of CaO, activated carbon and TiO2, prepared under mechanical milling. The composites were characterized by XRD, N2 physisorption measurements, and SEM-EDS; adsorption and desorption analysis was conducted via thermogravimetric analysis (TGA). The composites present homogeneous particle sizes, crystalline structure, cavities of different sizes at the surfaces, and are mesoporous. Adsorption of CO2 was measured at temperatures between 600°C and 660°C and the optimal was 650°C. The composite prepared with a percentage composition of chemical precursors of 94:3:3 and mechanical milling for 4 h, reached the maximum CO2 adsorption capacity of 0.474 g CO2/g, at 650°C under a 100% extra dry CO2 gas atmosphere for 4 h. Adsorption is attributed to the CaCO3 formation through a carbonatation process of CaO, and to the physicochemical features of the material. CO2 desorption from the composite was through decomposition of CaCO3 into CaO and CO2 by a calcination process at ≈ 850°C. These findings highlight the potential of these novel materials to be used for efficient CO2 capture at large scale, as a contribution to combating global warming and climate change.