Slow pyrolysis of Agave americana L. fibers: Analysis of kinetics and thermodynamics using the coats-redfern method at different heating rates

Abstract

This study employed thermogravimetric analysis (TGA) alongside the Coats-Redfern method (CRM) to investigate the thermal degradation's kinetics and thermodynamics of fibers extracted from the flower stalk of Agave americana (FSAA). We explored FSAA fibers' thermal behavior across varying heating rates (HRs) to elucidate complex reaction mechanisms and estimate critical parameters. TGA experiments at 5, 10, and 20 °C/min HRs reveal a multi-step breakdown process supported by solid coefficients of determination (R2 > 0.99). Activation energy values, ranging from 83.6 to 210.1 kJ/mol, vary with HR, providing insights into thermal decomposition kinetics. Thermodynamic parameters, including variations in entropy (ΔS), Gibb's free energy, and enthalpy, shed light on spontaneity and energy transfer during the process. Negative ΔS values suggested reduced disorder during thermal decomposition. This study represented a novel investigation into the thermal behavior of fibers extracted from the FSAA for the first time, using CRM in conjunction with TGA. Through comprehensive analysis, we elucidated the kinetics and thermodynamics of FSAA fiber degradation across various HRs. Our findings shed light on the intricate reaction mechanisms underlying FSAA fiber decomposition, providing valuable insights for potential applications in biofuel production and composite materials.