ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS, 2020 (SCI İndekslerine Giren Dergi)
The present study aimed to investigate the pyrolysis characteristics and kinetics of spent coffee waste (SCW) at different heating rates (5-40 degrees C/min) at a temperature ranging from 30 to 800 degrees C in a thermogravimetric analyzer (TGA). First, the physicochemical properties of the SCW were characterized using X-ray diffraction, Fourier transform infrared spectrometry, scanning electron microscopy, and elemental analysis. Then, the thermal decomposition kinetic profiles were modeled using the Coats-Redfern, Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Starink models. All the tested models provided accurate fits of the thermogravimetric analysis data with acceptably high R-2 values. The mean activation energy of the coffee waste was 101.8, 96.7, and 97.1 kJ/mol for the FWO, KAS, and Starink models, respectively. Finally, the evolved gases detected during the decomposition by TGA coupled with a mass spectrometer (MS) primarily consisted of water, methane, and carbon dioxide.