Advances in sustainable solid adsorbent materials for CO ₂ capture: mechanisms, performance, and techno‑economic perspectives

Rising atmospheric CO2 concentrations, increasing from approximately 280 ppm to over 425.4 ppm by 2024, reflect the cumulative impacts of population growth, industrialization, and socioeconomic development. Solid-phase adsorption has emerged as a promising alternative to solvent-based capture technologies, offering advantages in energy efficiency, modularity, and environmental compatibility. This review provides a critical assessment of adsorption-based CO2 capture, focusing on heterogeneous porous sorbents including metal-organic frameworks (MOFs), zeolites, activated carbons, and porous organic polymers. Key aspects such as adsorption mechanisms, pore-structure optimization, surface functionalization, and performance under post-combustion conditions are examined. Liquid-phase systems, including nanofluids and ionic liquids, are discussed only when integrated into hybrid or sorbent-supported configurations, and are not treated as standalone adsorption media. Emphasis is placed on techno-economic analysis (TEA) and Technology Readiness Level (TRL) to link material performance with deployment feasibility. Adsorption-based systems currently operate at TRL 3-6, with TEA indicating CO2 capture costs below USD 60 t−1 in high‑concentration sectors. Despite progress, large-scale deployment is constrained by regeneration energy penalties, capital costs, and sorbent durability. This review highlights key research gaps, emphasizing process material co-design, cyclic stability, and pilot-scale validation, positioning adsorption-based CO2 capture as a critical pathway toward carbon-neutral energy systems.