Engineered Biomass Waste-Derived Activated Biochar Catalyst for Biodiesel Production from Jatropha curcas Oil

ZnCl₂ impregnation of the cellulosic precursor is an effective way to generate carbon catalysts with a mesoporous structure and high specific surface area. Herein, we attempt to explore the synthesis of Citrus Limonum Pericarpium (lemon peel), an activated biochar catalyst produced via pyrolysis and consequent sulfonation. The obtained biochar catalyst exhibited notable characteristics, including a high surface area of 863.0 m² g⁻¹ and a substantial sulfur content of 4.02 wt.% (1.25 mmol g⁻¹) by EDX. Following, analytical techniques, such as scanning electron microscopy, BET, X-ray diffraction, Fourier-transform infrared, and TGA, were conducted for a comprehensive analysis of the catalyst. Subsequently, we applied the catalyst to optimize the transesterification process of Jatropha curcas oil (JCO), yielding an impressive 95.2% ± 0.4% yield. The optimization parameters were established with a reaction duration of 60 min, a temperature of 100°C, 8 wt.% catalyst, and JCO: MeOH ratio of 1 : 20. Catalyst reusability was probed over seven subsequent cycles with the final yield observed of over 88.4% ± 0.6%, while the decrease in yield was explained by EDX analysis. In summary, our investigation successfully navigated the synthesis and practical application of a sulfonated porous biochar catalyst for JCO transesterification, achieving noteworthy yields while addressing environmental concerns.