Okonkwo Chinwe P, Ajiwe Vincent I E, Ikeuba Alexander I, Emori Wilfred, Okwu Modestus O, Ayogu Jude I
Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University Awka Nigeria
Materials Chemistry Research Group, Department of Pure and Applied Chemistry, University of Calabar Calabar Nigeria.
RSC Adv. 2023 Jun 28;13(28):19495-19507. doi: 10.1039/d3ra02456c. eCollection 2023 Jun 22.
This study presents an approach to produce biodiesel from using natural heterogeneous catalysts derived from raw, calcined, and acid-activated forms of waste snail shells. The catalysts were thoroughly characterized using SEM, and process parameters were systematically evaluated during biodiesel production. Our results demonstrate a remarkable crop oil yield of 58.87%, with kinetic studies confirming second-order kinetics and activation energies of 43.70 kJ mol and 45.70 kJ mol for methylation and ethylation, respectively. SEM analysis identified the calcined catalyst as the most effective, exhibiting remarkable reusability for continuous reactions running up to five times. Moreover, the acid concentration from exhaust fumes yielded a low acid value (B100 0.0012 g dm), significantly lower than that of petroleum diesel, while the fuel properties and blends satisfied the ASTM standards. The sample-heavy metals were well within acceptable limits, confirming the quality and safety of the final product. Our modelling and optimization approach produced a remarkably low mean squared error (MSE) and a high coefficient of determination (), providing strong evidence for the viability of this approach at an industrial scale. Our results represent a significant input in sustainable biodiesel production and underscore the enormous potential of natural heterogeneous catalysts derived from waste snail shells for achieving sustainable and environmentally friendly biodiesel production.
本研究提出了一种利用从废弃蜗牛壳的原始、煅烧和酸活化形式衍生的天然非均相催化剂生产生物柴油的方法。使用扫描电子显微镜（SEM）对催化剂进行了全面表征，并在生物柴油生产过程中系统地评估了工艺参数。我们的结果表明，作物油产率高达58.87%，动力学研究证实甲基化和乙基化的反应动力学为二级动力学，活化能分别为43.70 kJ/mol和45.70 kJ/mol。扫描电子显微镜分析表明煅烧后的催化剂最为有效，在连续反应高达五次的过程中表现出显著的可重复使用性。此外，废气中的酸浓度产生了较低的酸值（B100为0.0012 g/dm），明显低于石油柴油，而燃料特性和混合燃料符合美国材料与试验协会（ASTM）标准。样品中的重金属含量完全在可接受范围内，证实了最终产品的质量和安全性。我们的建模和优化方法产生了极低的均方误差（MSE）和高决定系数（），有力地证明了该方法在工业规模上的可行性。我们的结果为可持续生物柴油生产提供了重要贡献，并突出了源自废弃蜗牛壳的天然非均相催化剂在实现可持续和环境友好型生物柴油生产方面的巨大潜力。
