Biorefinery-integrated production of activated carbon from biomass: Process routes, modeling, and sustainability metrics

Activated carbon (AC) and biochar derived from biomass are central to circular and low-carbon biorefineries, yet scale-up requires integration of precursor selection, thermochemical routes, and sustainability metrics. This review synthesizes process routes for biorefinery-integrated AC production, from carbonization and physical/chemical activation to product characterization and application-driven performance. Feedstock diversity and operating conditions are evaluated regarding pore development (reported surface areas from ~100 to >3,200 m²/g), yield, and environmental burdens, and a decision matrix is proposed to guide precursor selection across major biomass categories. Mechanistic and kinetic models relevant to design and scale-up (e.g., distributed activation energy models, shrinking-core models, and pore-evolution approaches) are summarized, along with data-driven machine-learning tools for property prediction and operational optimization. Finally, techno-economic and life-cycle evidence is consolidated, highlighting chemical recovery, greener activators, and key trade-offs (water, salts, greenhouse gases) relative to coal-derived AC. The review concludes with a roadmap for deploying advanced carbon materials within integrated bioeconomy systems.