Kinetic and thermodynamic studies of biomass pseudo-components under thermo-oxidative degradation conditions using asymmetric function of Bi-Gaussian as deconvolution technique

This work aimed at investigating the kinetic and thermodynamic characteristics of components of pine sawdust (PS), edible fungi spent substrate (FVSS) and their blend during thermo-oxidative degradation. The novelty focused on applying deconvolution technique to distinguish an overlapped peak into three individual peaks corresponding to pseudo-hemicellulose, pseudo-cellulose and pseudo-lignin, respectively. Particularly, the function of Bi-Gaussian was employed to capture the asymmetric reaction shapes. Mass loss was recorded using a thermal analyzer at heating rates of 10, 20 and 30 K min-1 in air atmosphere. Methods of Starink and master-plots were used for estimating kinetic triplet. The average activation energies of FVSS are lower than PS, with an order of pseudo-lignin > pseudohemicellulose > pseudo-cellulose corresponding to the ranges of 211.70-342.78, 139.00-172.53 and 128.08-146.99 kJ mol-1, respectively. The pre-exponential factor are all higher than E+10 s-1 demonstrating some simple complex chemical reactions occurred. Models of D2 and A1 dominate the degradation of pseudo-hemicellulose and pseudo-cellulose, respectively, in PS and the blend. The average values of DS, DH and DG are -51.62-146.31 J mol-1, 122.99-335 kJ mol-1 and 78 144.87-216.59 kJ mol-1, showing the non-spontaneous process and need energy to maintain. (c) 2022 Elsevier Ltd. All rights reserved