Enhancement of engineered biochar functionality through co-pyrolysis of municipal wastes over metal-doped catalysts

The escalating global waste crisis demands innovative valorization strategies. This study investigates the in-situ catalytic pyrolysis of municipal solid and food wastes to transform this stream into engineered biochar with tailored properties. Unlike prior research that primarily focuses on bio-oil upgrading, this work uniquely prioritizes biochar engineering by systematically evaluating three distinct catalyst families-HZSM-5 (Br & oslash;nsted acid), Na-ZSM-5 (basic/neutral), and Fe3O4 (redox-active)-and their modification with nickel or cobalt (5 wt%). Pyrolysis at 550 degrees C was selected based on thermogravimetric analysis to optimize the trade-off between biochar yield and carbonization degree. HZSM-5-based catalysts maximized biochar yield (40.9%), while Fe3O4-based catalysts favored bio-oil and biogas production. Metal coating generally reduced bio-oil yield, promoting non-condensable gas formation. Critically, catalyst selection and coating dictated biochar properties. Base catalysts, particularly Fe3O4, produced biochar with high specific surface areas (up to 480 m(2)/g). However, metal coating introduced catalyst particles onto the biochar surface, observed via FESEM/EDX, which reduced this area but significantly enhanced thermal stability (as low as similar to 15% weight loss by TGA). ... mehrThese findings demonstrate that catalytic pyrolysis can strategically tailor biochar, creating composites with active sites and robust stability. This positions waste-derived biochar as a promising, sustainable material for advanced applications, including catalysis and energy storage, particularly after post-processing to reclaim surface area.