Ceramics-Silikáty 68, (4) 556 - 564 (2024)

Waste concrete generated from building projects was used to prepare a solid adsorbent using the alkali fusion hydrothermal synthesis method, aiming to reduce the cost of the CO₂ capture. The microstructure of the adsorbent materials was analysed using characterisation techniques, including Scanning electron microscopy (SEM), FT-IR spectroscopy, and X-ray diffraction. The results indicate that the synthesised adsorbent has a crystalline structure. The maximum CO₂ adsorption capacity of the synthesised adsorbent reaches up to 2.12 mmol/g^-1 at 303 K. The results indicated that the synthesised adsorbent exhibits a significantly high CO₂ adsorption capacity and CO₂/N₂ selectivity. The life cycle assessment (LCA) of the adsorbent synthesis process revealed a minimal environmental impact on the greenhouse effect and water pollution, measured at 6.15 kg CO₂ eq and 2.76 kg 14^-DB eq, respectively. The results suggest that utilising waste concrete to prepare a CO₂ adsorbent is feasible, offering a new environmentally friendly approach for waste concrete resource utilisation.