<p>Agricultural and textile waste management presents significant environmental challenges globally. This study explores an innovative approach to biochar production through co-carbonization of plantain stalks with polyester fabric waste. Plantain stalks (90%) were combined with waste polyester fabric (10%) and processed using an auto-thermal carbonization reactor. The hybrid biochar demonstrated superior properties compared to plantain stalk-only biochar. The hybrid biochar achieved a 39.6% yield at 426.7 °C versus a 37.2% yield at 395.93 °C for the pristine biochar. Surface characterization revealed significant improvements: the hybrid biochar exhibited 29% greater surface area (492.172 m²/g), 9% higher pore volume, and 15% larger pore diameter compared to the pristine biochar. The surface of the hybrid biochar was smoother and had clumps of particles, and the analysis of its elements showed it had more potassium than the regular biochar. Functional group analysis confirmed retention of key functional groups. These findings demonstrate the potential for converting dual waste streams into enhanced biochar products, supporting circular economy principles and sustainable waste management. The improved properties suggest applications in agriculture, environmental remediation, and material science. This research addresses the pressing need for innovative waste management solutions while creating value-added products from agricultural and textile waste.</p> Graphical abstract <p></p>