Microwave-Assisted Conversion of Waste Coffee Grounds to Turbostratic Carbon

Abstract

The abundance of waste coffee grounds led to an adverse effect in our environment. This study focuses on generating carbon with conventional microwave for energy efficiency. The carbon result of conventional microwave carbonization is being compared to furnace and microwave-furnace processes. Before the conversion, Thermogravimetric Analysis (TGA) was performed to determine the degradation temperature of the waste coffee grounds. In addition, Fourier Transform Infrared Spectroscopy (FTIR) was employed to elucidate the presence of organic functional groups in the samples. Absence of significant peaks from the carbonized coffees spectrum confirms degradation. X-ray Diffraction (XRD) analysis was also performed to monitor the effect of temperature as shifting, and formation of peaks are seen. Identified peaks with Miller indices of (002), (101), and (004) signifies the presence of carbon. Scanning Electron Microscopy (SEM) paired with Energy Dispersive X-ray spectroscopy (EDX), shows the difference in morphology for the dried coffee and the carbonized coffees as well as the strong presence of carbon from the microwave-assisted carbonization which is about 74%.