Valorization of Corncob and Khat Waste into Biochar via Decentralized Multi-Purpose Pyrolysis Stoves

The escalating global waste crisis necessitates sustainable valorization strategies, with biochar production emerging as a promising solution for converting organic residues into a carbon-rich material. This study evaluated biochar derived from corncob and khat waste pyrolyzed using allo-thermal and auto-thermal multi-purpose stoves. Biochar was fractionated into four particle sizes (>2 mm, 1–2 mm, 0.6–1 mm, and 2 mm) to 6.6 mS/cm (<0.6 mm). This study demonstrates that decentralized biochar production using multi-purpose stoves can yield materials with tunable properties, and that khat waste—an underutilized regional resource—shows particular promise for producing high-ash, high-EC biochar suitable for acidic soil amendment.