LTA zeolite adsorbent is considered to be a promising material for capturing carbon dioxide (CO2), but its application faces challenges in terms of economy and adsorption capacity. This paper proposes a sustainable green synthesis strategy to construct the LTA (Na-LTA) zeolite precursor using industrial solid waste titania slag as raw material, and then prepare a series of cation-exchanged M-LTA (M: K, Ca, Ce) zeolite molecular sieves adsorbents through conventional liquid-phase ion exchange (LPIE) to adjust the cationic active sites. The dynamic adsorption test and weight adsorption test show that the saturated adsorption capacity of all M-LTA zeolite molecular sieves has been improved, but the penetration adsorption capacity of K-LTA is significantly reduced, which is related to the lower adsorption rate and pore volume. The Ca-LTA type zeolite significantly improved the CO2 capture capacity and CO2/N2 and CO2/CH4 separation rate, and maintained excellent cyclic stability after five cycles of adsorption/desorption; it accelerated the CO2 adsorption rate, being 4.95 times that of the Na-LTA precursor; and according to the Langmuir-Freundlich isotherm model, the maximum adsorption capacity of Ca-LTA could reach 4.02 mmol/g. The CO2 adsorption process by Na-LTA zeolite is dominated by both physical and chemical adsorption. This study follows the environmental protection concept of "treating waste with waste" and provides important reference value for the resource utilization of solid waste and the improvement of environmental pollution through synergistic CO2 capture.