Surface-engineered nanostructured adsorbents for CO₂ capture: From material design to process integration and...

The growing necessity to curb CO₂ emissions from man-made sources has driven the development of highly efficient and economical approaches to carbon capture. The current review is intended to give an overview and critical analysis of nanomaterial-based adsorbents for CO₂ capture with specific consideration of the connections between nanomaterial properties, adsorption processes, process integration, and industrial application. As opposed to the majority of literature surveys, which concentrate on either certain classes of materials or adsorption capacity of various materials separately, the review proposes a holistic view by combining information on the correlations of pore structure, surface chemistry, thermodynamics, adsorption kinetics, selectivity principles, and regeneration behavior of different nanostructured adsorbents, such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), hierarchical nanoporous carbons, graphene analogs, silica hybrids, metal oxides, and bioinspired materials. Special focus is paid to surface engineering of adsorbents, including amine grafting, heteroatom doping, and compositing, and its influence on CO₂ affinity, cyclic stability, and transport properties of adsorbents. Apart from the lab-scale efficiency, it analyzes issues of scale-up, regeneration efficiency, process intensification, techno-economic viability, and life-cycle sustainability. New possibilities such as machine-learning aided design of new adsorbents, standardized performance measures, and the concept of circular economy are also discussed. This review acts as a guideline and framework for designing nanostructured adsorbents that can be used in carbon management on a large scale.