Co-pyrolysis of food waste with coconut fiber: thermogravimetric analyzes and hydrogen yield optimization

Abstract

ABSTRACT Co-pyrolysis of food waste with coconut fiber to produce hydrogen is considered an effective strategy for clean waste disposal and high value-added product synthesis. This study investigated the co-pyrolysis mechanism and hydrogen yields of food waste and coconut fiber at different blending ratios by thermogravimetric analysis and regression optimization. A heating rate of 10 ℃/min ranging from 30 ℃ to 900 ℃ coupled with the Svante August Arrhenius kinetic equations were utilized to derive the activation energies of the samples. Thermogravimetric analysis presented positive synergistic effects between coconut fiber and food waste to accelerate weight loss rate, and the main pyrolysis peak (200 ~ 450 ℃) moved to low temperature areas as the coconut fiber proportion increased. Additionally, kinetics showed that the lowest activation energy was 29.28 kJ at 1:3 blending ratio of coconut fiber to food waste. Based on this, response surface methodology (RSM) by Design-Expert.V8.0.6 ((Box-Behnken Design) (BBD)) was applied to optimize the microwave co-pyrolysis parameters (1600 W microwave power, 5 mm feedstock size, and 74% food waste proportion), thus the predicted maximum hydrogen yield was 46.20 vol.%. This study contributes to ameliorating the potential for solid waste microwave co-pyrolysis for value-added products production, therefore providing a reference for the further development of clean disposal technology and waste resource utilization.