Co-pyrolysis of Diaper Cellulose and Sugarcane Bagasse: Investigating Kinetics, Thermodynamics, and Possible Synergies

Abstract

This research involves the blending of readily accessible waste materials, namely diaper cellulose (DC) and sugarcane bagasse (SB), for a comprehensive thermodynamic and kinetic analysis during co-pyrolysis. Thermogravimetric analysis (TGA) has been conducted to undertake a co-pyrolysis investigation across different ratios of DC and SB. The analysis covered a temperature sequence of 20°C–800°C with varying heat flow rates of 10°C/min, 20°C/min, and 30°C/min. For activation energy determination, the Kissinger–Akahira–Sunose (KAS) and Ozawa–Flynn–Wall (OFW) methods were employed. The average activation energy, calculated using the OFW and KAS methods, was found to have values in the range of 209.46 and 226.109 kJ/mol for DC, 139.08 and 157.41 kJ/mol for 50DC-50SB, and 102.19 and 109.758 kJ/mol for SB, respectively. The activation energy data of the mixtures were shown to be decreasing from the pristine DC. Notably, the mixture exhibited a lower activation energy, indicating a positive synergistic effect resulting from co-pyrolysis. Thermodynamic parameters such as ΔH, ΔS, and ΔG for the mixture were also evaluated. The Gibbs free energy (ΔG) across samples varied between 288.71 and 123.05 kJ/mol for pure DC, DC-SB mixtures, and pure SB, demonstrating a notable influence on co-pyrolysis. The observed decrease in energy levels in the mixture suggests that the combination of sugarcane bagasse with diaper cellulose results in a reduced energy demand. The activation energy, determined through thermogravimetric analysis (TGA), delivers valuable insights into the thermal decomposition behavior of materials. The TGA data help in illustrating the thermal constancy of materials, allowing researchers to assess the suitability of substances for specific applications. In industries such as pharmaceuticals, polymers, and chemicals, TGA with activation energy determination can be employed for quality control purposes. The calculated thermodynamic data are crucial in designing and optimizing pyrolysis and gasification processes. They aid in predicting the rate of thermal decomposition, optimizing reaction conditions, and improving the efficiency of these processes for bioenergy production or waste treatment. TGA with activation energy analysis is extensively used in the polymer industry. It assists in understanding the degradation kinetics of polymers, enabling the development of heat-resistant materials for specific applications. Also, these values are essential in catalyst design for chemical reactions. They guide the selection and optimization of catalysts for various processes, ensuring efficient and economical chemical transformations. Determining the activation energy of fuels provides critical information for combustion processes. This is useful in optimizing combustion conditions for energy production, as well as in assessing the stability and safety of fuel storage.