Effect of Thermal Treatment on Functional Group Transformation of Empty Fruit Bunch (EFB) Biomass at 150–200°C: An FTIR Spectroscopic Analysis

Abstract

Empty Fruit Bunch (EFB) is a lignocellulosic biomass waste with potential as renewable energy through thermal processing. This study analyzes chemical functional group changes in EFB heated between 150°C and 200°C using Fourier Transform Infrared (FTIR). Results show shifts and decreasing intensities of primary functional groups with rising temperatures. At 150°C, FTIR spectra exhibited dominant hydroxyl (–OH) groups at 3616.37 cm⁻¹ and methyl/methylene (C–H) groups at 2918.61 cm⁻¹. Increasing the temperature to 170°C significantly reduced the intensity of –OH groups, shifting peaks to 3495.39 cm⁻¹, and formed aromatic C=C groups at 1591.46 cm⁻¹, indicating the initiation of hemicellulose decomposition. At 200°C, polar –OH groups decreased drastically by over 90% compared to 150°C, leaving a weak peak at 3044.24 cm⁻¹. The stable aromatic C=C group at 1592.96 cm⁻¹ indicated lignin dominance post-heating. Peaks of aromatic C–O and C–H bonds strengthened in the 500–900 cm⁻¹ range, suggesting aromatic carbon compound formation. Results indicate 200°C as optimal for enhancing EFB quality as a solid fuel, yielding a stable, hydrophobic chemical structure. This study provides insights into effectively optimizing EFB waste utilization for alternative energy through thermal modification.