Effect of Co and Ni impregnated ZSM-5 catalyst on pyrolysis products of Tithonia diversifolia: Kinetic study and thermodynamics

Abstract

Addressing the need for sustainable alternative fuels amid depleting petroleum resources and environmental concerns, this study investigates the conversion of abundant and eco-friendly lignocellulosic biomass, the invasive weedy plant Tithonia diversifolia (TD), through pyrolysis to bio-oil. The influence of ZSM-5 catalysts with Ni and Co impregnation is also explored on fixed bed-pyrolytic conversion as well as employing various kinetic and thermodynamic models. Characterization techniques including XRD, SEM, and EDX confirm successful metal loading while preserving microstructure. Catalysts significantly impact product distribution, and physicochemical analysis alongside NMR and GC-MS data reveal improved bio-oil properties, including reduced O content, increased C content, and higher calorific values when catalysts are employed. Kinetic analysis suggests lower activation energies for catalytic pyrolysis (Ea∼105–154 kJ/mol) compared to non-catalytic processes (Ea∼160 kJ/mol), emphasizing the catalytic role in enhancing biomass conversion. Thermodynamic analysis further supports catalytic enhancements of biomass devolatilization. This study offers valuable perspectives on the pivotal role of catalysts in biomass conversion.