Caesalpinia ferrea: a potential feedstock for biochar production

In the present study, a lignocellulosic from inedible fruits of Caesalpinia ferrea (CFIF) — a tree mainly found in Brazil and Bolivia — was studied as potential biomass for production of biochar under different pyrolysis temperatures. The characterization of the biochars were done using different techniques: chemical composition, elemental analysis, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), small-angle X-ray scattering (SAXS), and scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS). The chemical composition showed a higher amount of lignin, extractives, moisture, and hemicellulose than the most common fibers in literature. The considerable presence of the aforementioned components contributed to the low thermal stability observed in TGA. As a result, the complexes formed are initially less ordered and become more ordered at higher temperatures. The elemental analysis showed that the carbon content increased with pyrolysis temperature while the nitrogen and hydrogen followed the opposite trend, influencing the final biochar elements, also confirmed by SEM/EDS. CFIF have potential for the production of biochar using isothermal and non-isothermal processes based on the selection of appropriate conditions.