Effects of green and innovative pretreatment techniques on kinetic parameters of sunflower seed husk

Abstract

The effects of green pretreatment processes, such as ultrasonic process (US) and deep eutectic solvent (DES), applied to the biomass on kinetic parameters are as important as their effects on characteristic properties. Process conditions and course of reaction progression depend on the knowledge about kinetic parameters, activation energy and reaction model of thermal degradation in scale-up studies. Therefore, in this study, the change in the kinetic parameters with US applied with both distilled water and DES (glycerol:sodium acetate) at 100 W power and 20 kHz frequency for 10 minutes to sunflower seed husk (SSH) was revelaed. Isoconversional methods Kissinger-Akahira-Sunose (KAS) and Flynn- Wall-Ozawa (FWO) were preferred for the evaluation of activation energy of SSH and pretreated SSH at 15°C/min, 20°C/min and 25°C/min heating rates. US pretreatment with DES instead of water resulted in increment of average activation energy values (Ea) from 113.13 to 143.65 kJ/mol in the KAS method. Ea values for all SSH samples changed in the range of 87.72-143.65 kJ/mol and higher Ea values was obtained with KAS method for pretreated SSH samples. Consequently, the use of DES in US pretreatment was more effective to change kinetic parameters of SSH compared to water.