This work aimed to study the kinetic of thermal degradation of red pepper waste as solid biofuel to bioenergy production. The thermal degradation experiments were conducted at three heating rates, 5°C/min, 7.5°C/min and 10°C/min in a thermogravimetric analyzer and oxidative atmosphere. The kinetic analysis was carried out applying the isoconversional model of Ozawa-Flynn-Wall. The activation energy was considerate low and varied 29.49-147.25k J/mol. The enthalpies revealed the energy difference between the reagent and the activated complex agreed with activation energies, the values of the pre-exponential factor indicated empirical first order reactions, Gibbs free energy varied from 71.77 kJ/mol to 207.03 kJ/mol and the changes of entropies had negative values, indicating that the degree of disorder of products formed through bond dissociations was lower than initial reactants. The calorific value was 19.5 MJ/kg, considered a relevant result for bioenergy production.

This work aimed to study the potential use of pyrolyzed orange peels as solid biofuels and biosorption of heavy metals. The dry biomass and the biofuel showed moderate levels of carbon (44-62%), high levels of oxygen (30-47%), lower levels of hydrogen (3-6%), nitrogen (1-2.6%), sulfur (0.4-0.8%) and ash with a maximum of 7.8%. The activation energy was calculated using Kissinger method, involving a 3 step process: volatilization of water, biomass degradation and volatilization of the degradation products. The calorific value obtained was 19.3MJ/kg. The studies of metal biosorption based on the Langmuir model obtained the best possible data fits. The results obtained in this work indicated that the potential use of waste orange peel as a biosorbent and as a solid biofuel are feasible, this product could be used in industrial processes, favoring the world economy.

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The inadequate and indiscriminate disposal of sugarcane bagasse (SCB) has received much attention. The exploration of bioenergy properties of biomasses and its biochars play an important role in achieving their utilization. In this context, understanding thermal conversion processes of biomass and biochars it is crucial to use them at bioenergy production. The aim of this study was to investigate thermal behavior of SCB biomass residue, as well as his biochar, by thermogravimetric analysis (TG), including thermodynamic parameters for non-isothermal analyses using Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS) and Friedman, kinetic isoconversional methods. Thermal analyses were conducted under oxidative and inert atmosphere at heating rates of 5, 7.5 and 10°C min-1. The hemicellulose maximum mass loss rate was at 250°C, cellulose at 330°C and lignin decomposition from 190 to 500°C, but the maximum mass loss rate at 430°C, the devolatilization was at *200°C. The variation of apparent E a represents single-step kinetics on the degradation process and OFW model is in better accordance with the experimental data and satisfactorily described the complexity of degradation process. SEM/ EDX analyses showed carbon, oxygen, aluminum, magnesium and iron.

In order to minimize environmental problems related to the generation and disposal of spent mushroom substrate (SMS) from mushroom cultivation activities, this study aimed to evaluate the thermal behaviour of the spent shiitake substrate (SSS) and its resulting biochar. Analyzing biochars produced at a temperature of 350 °C (BC350) was found to be that with the highest energy potential due to a reduced amount of resulting ash and nitrogen, and larger amounts of carbon, hydrogen, fixed carbon, as well as a higher calorific value, gravimetric yield, and gravimetric yield factor. SSS and BC350 were used in thermogravimetric and kinetic analyses. Thermogravimetric analyses were carried out at three heating rates, 10, 15, and 20 °C/min in an oxidizing atmosphere. Conversion steps relating to water loss and degradation of hemicellulose, cellulose, and lignin have been identified. The kinetic study was carried out by non‐isothermal and non‐isoconversional Kissinger method. The activation energies obtained were 110 and 136 kJ · mol−1 for the SSS and BC350, respectively, and are well within the range found for other lignocellulosic materials, such as bagasse and wheat straw. The pre‐exponential factor, in the order of 108, indicated the presence of complex elements.