Kinetic insights and optimization of catalytic pyrolysis from brown macroalgae: evaluation of commercial catalyst performance

Abstract This study investigates the catalytic pyrolysis of Padina pavonica using Amberlyst-15 and ZSM-5 catalysts to optimize bio-oil yield and quality. The hypothesis suggests that these catalysts enhance bio-oil production via deoxygenation and selective cracking. Using response surface methodology and kinetic analysis, the effects of catalyst loading, temperature, and reaction time were evaluated. Amberlyst-15 at 2% loading produced the highest bio-oil yield of 49.8%, compared with 18.23% from non-catalytic pyrolysis. ZSM-5 achieved 48.54% bio-oil yield, with a higher gas yield (22.6%) and hydrocarbon yield of 40.8%. Amberlyst-15 yielded up to 49.8% aromatic hydrocarbons. While both catalysts increased solid residue, ZSM-5 produced more char. Kinetic analysis showed Amberlyst-15 exhibited superior catalytic activity at elevated temperatures, with higher reaction rate constants and activation energy. These findings optimize catalytic pyrolysis for macroalgae-based biofuel production, maximizing bio-oil yield and hydrocarbon content for large-scale applications.