Carbon footprint of biomass-derived activated carbon: life cycle assessment, environmental sustainability, and carbon-negative potential.

Biomass-derived activated carbon has emerged as a sustainable alternative to conventional fossil-based activated carbon owing to its renewable origin, excellent adsorption performance, and potential to support circular bioeconomy and climate mitigation strategies. However, its overall environmental sustainability depends not only on the renewable nature of biomass feedstocks but also on greenhouse gas emissions generated throughout production, utilization, regeneration, and end-of-life management. This review critically reviews the carbon footprint of biomass-derived activated carbon from a life cycle perspective, emphasizing the influence of feedstock selection, production technologies, activation methods, transportation, energy consumption, and chemical utilization on environmental performance. The application of life cycle assessment (LCA) and carbon accounting frameworks for quantifying greenhouse gas emissions, identifying environmental hotspots, and evaluating carbon-negative potential is comprehensively discussed. Comparative analyses of diverse biomass feedstocks and recent experimental studies demonstrate that agricultural residues generally exhibit lower environmental burdens than fossil-derived precursors, although sustainability remains highly dependent on process design, regional energy systems, and methodological assumptions. Emerging applications in water purification, air pollution control, carbon dioxide capture, catalysis, energy storage, hydrogen storage, and soil carbon sequestration further illustrate the multifunctional role of biomass-derived activated carbon in sustainable development. Finally, current challenges, knowledge gaps, and future research priorities are highlighted to facilitate the development of low-carbon, resource-efficient, and industrially scalable activated carbon production systems.