Integrated Kinetic and Thermodynamic Evaluation of Corn Cob Derived Nanomaterials from Agro-Waste Using Thermodilatometric Analysis for Sustainable Energy Application

Abstract

Corn cobs, an abundantly available agricultural residue, hold significant promise as a renewable feedstock for sustainable bio-energy production. This study provides a detailed investigation of their pyrolytic decomposition behavior, kinetic parameters, and thermodynamic characteristics using non-isothermal TGA (thermogravimetric analysis). Experiments were performed in an inert nitrogen atmosphere within a 25 - 700 °C temperature range, applying multiple (5, 10, 15, and 20 °C/min) heating rates. To determine the reaction kinetics, three well-established model-free iso-conversional approaches, KAS (Kissinger Akahira Sunose), FWO (Flynn Wall Ozawa), and Starink methods were utilized. The mean activation energies obtained were 209.1 kJ/mol (FWO), 207.5 kJ/mol (KAS), and 209.3 kJ/mol (Starink), each displaying strong correlation coefficients (R² ≈ 0.91 - 0.92), validating the reliability of the kinetic modeling. Thermodynamic analysis using the KAS method revealed a ΔH (enthalpy change) of 204.4 kJ/mol, a ΔS (entropy change) of 82.2 J/mol·K, and a ΔG (Gibbs free energy change) of 155.2 kJ/mol. These findings indicate that corn cob pyrolysis is an endothermic and non-spontaneous process, reflecting the inherent energy requirements and thermal stability challenges during conversion. Nevertheless, the results highlight corn cobs as a viable and cost-effective biomass resource for thermochemical energy applications, offering substantial potential for sustainable fuel generation.