Title: Sustainable Food Waste Management: Synthesizing Engineered Biochar for CO₂ Capture

Abstract: Humanity needs innovative ways to combat the environmental burden caused by food waste, which is one of the critical global issues. We proposed food waste-derived engineered biochar (FWDEB) for CO₂ capture from a life cycle perspective. FWDEB samples were prepared by carbonization and chemical activation for CO₂ adsorption. FW400-KOH600(2), carbonized at 400 °C and then activated at 600 °C with a KOH/biochar mass ratio of 2, presented the best CO₂ adsorption capacities of 4.06 mmol g^–1 at 0 °C (1 bar) and 2.54 mmol g^–1 at 25 °C (1 bar) among all prepared samples. The CO₂ uptake at 25 °C (1 bar) was affected by both micropore volume and surface area limited by narrow micropores less than 8 Å. Basic O- and N-functional groups were generated during the KOH activation, which are beneficial for enhancing the FWDEB-based CO₂ adsorption. Moreover, a life cycle assessment was implemented to quantify the potential environmental impacts of FW400-KOH600(2), indicating that negative net global warming potential could be achieved using the FWDEB-based CO₂ capture approach. Owing to the environmental benefits, we highlighted its potential as a promising technical route to mitigate climate change and achieve a waste-to-resource strategy.