Effect of copper wire additive on the properties of Anonychium africanum pod biochar produced in a two-chamber top-lit updraft gasifier

Abstract

Inefficient biomass conversion causes significant carbon loss and environmental pollution, necessitating controlled gasification approaches that maximize biochar quality and functional performance. This study investigated the effect of copper additives on the yield and properties of Anonychium africanum biochar produced in a two-chamber gasification system. Anonychium pods were gasified at 350 °C for 130 min with and without copper wire additives at a 50:50 pod-to-copper mass ratio, followed by material characterization. The copper-catalyzed system produced 42 ± 5.1% yield compared with 46 ± 3.8% for uncatalyzed conversion. Copper catalysis increased the BET surface area from 170.571 to 278.956 m²/g and Langmuir surface area from 385.999 to 1180.825 m²/g, while carbon and nitrogen contents increased from 61.32% to 75.50% and 14.88% to 18.56%, respectively. Morphological analysis revealed transformation from mineral-coated flakes to well-defined polygonal structures with extensive pore exposure. FTIR confirmed enhanced aromatic condensation and reduced oxygenated functionalities. Notably, EDX detected no copper in the biochar, indicating contact catalysis rather than doping. Overall, copper additives modified carbonization pathways, producing engineered biochars with enhanced structural stability and functional properties, with potential applications in environmental remediation, catalysis, and soil amendment.