Comparative insights into pyrolysis and co-pyrolysis pathways: A review of tailored carbonaceous adsorbents for CO₂ capture and waste valorization

Abstract\. Escalating atmospheric CO₂ emissions represent one of the most critical environmental challenges of the 21st century, driving an urgent search for mitigation strategies that are both effective and sustainable. In parallel, the growing emphasis on circular economy principles has stimulated interest in waste-derived carbonaceous materials as viable sorbents for CO₂ capture. Against this backdrop, thermochemical pyrolysis has been extensively investigated as a viable pathway for converting diverse waste feedstocks into solid carbon materials with tunable adsorption properties. Despite substantial progress in this field, a comparative understanding of carbonaceous sorbents derived from single feedstock pyrolysis and blended feedstock co-pyrolysis remains limited, hindering the development of tailored carbon-based CO₂ adsorbents. This review addresses this gap by evaluating the CO₂ adsorption performance of solid carbon sorbents produced through thermochemical conversion routes. It further examines how feedstock selection, blending ratios, and processing conditions influence the structural and surface characteristics that govern CO₂ uptake. Textural properties, surface chemistry, and CO₂ adsorption performance are examined to compare sorbents derived from single and blended feedstocks. The analysis focuses on carbonization and activation strategies relevant to systems incorporating plastic waste. Furthermore, critical challenges associated with feedstock compatibility, catalyst effects, techno-economic feasibility, and the emerging application of machine learning approaches for predicting CO₂ capture performance are discussed. Overall, this review bridges existing knowledge gaps and offers strategic insights for the development of efficient, scalable, and sustainable carbonaceous adsorbents for CO₂ capture applications.