Microwave-driven transformation of CO2 adsorbents regeneration: A comprehensive review from principles to system designs

• Microwave assisted regeneration of CO 2 adsorbents was comprehensively reviewed. • Influence of dielectric loss and hotspots on regeneration performance was analyzed. • Design strategies for microwave-responsive adsorbents with high efficiency were summarized. • Engineering and scale-up principles for microwave regeneration reactors were proposed. Conventional temperature-swing adsorption (TSA) for CO 2 capture is energy intensive, typically requiring above 3.5 MJ/kg CO 2 . Microwave-assisted regeneration technology has emerged as a promising alternative strategy due to the unique volumetric heating and selective heating advantages of microwave heating. This review provides a comprehensive analysis of the mechanisms and applications of microwave-enhanced adsorbent regeneration of CO 2 adsorbents. First, the fundamental principles of microwave-induced TSA process intensification are elucidated by establishing correlations between the dielectric loss factor ε″ of CO 2 adsorbents and their key performance, including regeneration energy demand and desorption rate, highlighting the role of microwave-induced hotspots. Consequently, the review summarizes the design principles and synthesis strategies from diverse fields for engineering microwave-responsive adsorbents with targeted microwave-absorbing capability. Next, this review expands the scope to reactor-scale considerations and process integration, where the impact of system design, including impedance matching, cavity geometry, power feeding strategies, and gas-solid hydrodynamics, on overall energy utilization and temperature uniformity is examined. A comparative analysis of fixed-bed, fluidized-bed, and moving-bed configurations within microwave fields is presented, highlighting their respective synergies and operational constraints for scalable regeneration. Moreover, significant scientific and engineering challenges of microwave-assisted regeneration technology are reviewed, including insufficient fundamental understanding of quantitative relationships between hotspot intensity, desorption kinetics and long-term adsorbent deactivation, as well as scale-up problems associated with heating uniformity and limited microwave penetration depth. It remains an essential need to develop unified engineering guidelines by bridging advanced multiphysics modelling with practical reactor design, with the aim to achieve large scale and low energy CO 2 capture by establishing a competitive technological pathway.