Production of High-Efficiency Bio-Briquettes via Carbonization of Coconut Shells and Comparative FTIR Spectroscopic Analysis

This research investigates the conversion of agricultural waste into a sustainable energy carrier through the production and characterization of bio-briquettes derived from coconut (Cocos nucifera) shells. As global energy demands shift toward renewable alternatives to mitigate the environmental impact of fossil fuels, the densification of biomass residues presents a viable pathway for decentralized energy production. This study specifically focuses on the carbonization process. a thermochemical conversion method to enhance the energy density and combustion profile of the raw material. The experimental method involves the collection, cleaning, and crushing of raw coconut shells, followed by carbonization in a specialized kiln at temperatures ranging from 300∘C to 500∘C. A critical component of this study is the analytical characterization using Fourier Transform Infrared (FTIR) spectroscopy to evaluate the chemical structural transformations occurring during the thermal treatment. FTIR analysis was conducted on both the raw (pre-carbonization) and charred (post-carbonization) samples to identify functional group changes. The raw coconut shell spectra exhibited prominent peaks associated with hydroxyl groups (−OH), aliphatic C−H stretching, and carbonyl groups (C=O), reflecting the complex lignocellulosic matrix of cellulose, hemicellulose, and lignin. Post-carbonization FTIR results demonstrate a significant reduction of these oxygenated functional groups, indicating the dehydration and decarboxylation of the biomass, which contributes to the increased hydrophobicity and stability of the resulting charcoal. To ensure structural integrity for transport and use, the carbonized fines were blended, specifically cassava starch and corn starch, at varying concentrations (5%, 10%, and 15%). The physical and thermochemical properties of the produced briquettes were rigorously tested, including bulk density, shatter resistance, and proximate analysis (moisture, ash, volatile matter, and fixed carbon). This study concludes that the integration of carbonization and densification, validated by FTIR molecular insights, provides a robust framework for transforming coconut waste into a high-performance, carbon-neutral fuel source suitable for both domestic and industrial applications.