Halloysite nanotubes-based adsorbents for carbon capture and secondary utilization: Recent developments and future prospects

Rising atmospheric CO 2 concentrations have intensified the need for efficient capture technologies coupled with sustainable end-use pathways. Halloysite nanotubes (HNTs) and HNTs-rich materials are emerging as promising sorbent platforms due to their natural abundance, mechanical robustness, tubular morphology, and tunable surface chemistry. This review summarizes recent developments in HNTs-based materials for carbon capture, focusing on adsorption mechanisms, structure–property relationships, and performance gains enabled by thermal and mechanochemical activation, acid/alkali treatment, amine grafting or impregnation, and hybridization with polymeric or porous phases. Although these materials do not always outperform high-end synthetic sorbents in absolute uptake, they remain attractive because of their lower cost, simpler processing, and potential for post-capture reuse. Beyond capture, promising reuse pathways for spent adsorbents include soil amendment, construction materials, dye removal, fire retardancy, antibacterial applications, and catalysis. Overall, HNTs-based materials offer a compelling route toward integrated carbon management, scalable deployment, and resource-efficient valorization in practice.