Biological waste materials are rich sources of important minerals such as calcium and potassium, which are required in the preparation of effective biocatalysts for biodiesel production. Their adoption into green catalyst production is becoming important due to the ease of process synthesis and the availability of waste animal shells and agricultural materials. In this study, the potential of a bi-component, heterogeneous catalyst of fused chicken eggshells and pawpaw peels was tested in the transesterification reaction of linseed oil. The waste materials, separately, were dried and calcined at 900 °C or at 700 °C for 3 h to obtain their calcined ashes (calcined eggshells (CES) and calcined pawpaw peels (CPP)). The CES and CPP were then bonded by the wet impregnation method (by dissolving each ash at weight concentration of 7:3 CES/CPP in 100 mL warm distilled water and further calcining them at 600 °C for 2 h). The catalyst that was developed was characterized using Scanning Electron Microscopy - Energy Dispersive X-Ray Spectroscopy (SEM–EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The Box–Behnken design was applied to generate 15 experimental runs, which were used to investigate the effect of the operational parameters such as methanol-to-oil molar ratio, catalyst loading, and reaction time. The characterization results show that the ash is very rich in Ca and K ions. The best reaction condition for the transesterification process was found to be a methanol / oil molar ratio of 14.9:1, catalyst loading of 3.78 wt%, process reaction time of 80 min at constant reaction temperature of 65 °C with a biodiesel maximum yield of 91.20 wt%. The physicochemical properties of the produced biodiesel were measured and found to meet the American Society for Testing of Materials (ASTM) and European National (EN) standards and South African National Standards (SANS) biodiesel quality standards. The fused catalyst can be reused for up to five cycles with little reduction in yields. The study demonstrates the potential of utilizing biomass feedstock in developing effective and sustainable biodiesel fuels. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

中文翻译：

---

一种有效的绿色和可再生多相催化剂，源自双组分生物废物材料的融合，用于优化亚麻油甲酯的酯交换

生物废料是重要矿物质（如钙和钾）的丰富来源，是制备用于生物柴油生产的有效生物催化剂所必需的。由于工艺合成的简便性以及废弃动物壳和农业材料的可用性，它们在绿色催化剂生产中的应用变得越来越重要。在这项研究中，在亚麻籽油的酯交换反应中测试了融合鸡蛋壳和木瓜皮的双组分多相催化剂的潜力。分别将废料干燥并在 900°C 或 700°C 下煅烧 3 小时以获得它们的煅烧灰分（煅烧蛋壳（CES）和煅烧木瓜皮（CPP））。然后通过湿浸渍法将 CES 和 CPP 粘合在一起（通过以 7 的重量浓度溶解每种灰分：3 CES/CPP 在 100 mL 温蒸馏水中，并在 600 °C 下进一步煅烧 2 小时）。使用扫描电子显微镜 - 能量色散 X 射线光谱 (SEM-EDX)、X 射线衍射 (XRD) 和傅里叶变换红外光谱 (FTIR) 对开发的催化剂进行表征。Box-Behnken 设计用于生成 15 个实验运行，用于研究操作参数的影响，例如甲醇与油的摩尔比、催化剂负载和反应时间。表征结果表明，灰分富含钙离子和钾离子。发现酯交换过程的最佳反应条件是甲醇/油摩尔比为 14.9:1，催化剂负载量为 3.78 wt%，在 65°C 恒定反应温度下工艺反应时间为 80 分钟，生物柴油最大产率为91.20 重量％。对生产的生物柴油的理化特性进行了测量，发现其符合美国材料测试协会 (ASTM) 和欧洲国家 (EN) 标准以及南非国家标准 (SANS) 生物柴油质量标准。熔融催化剂最多可重复使用五个循环，而收率几乎没有降低。该研究证明了利用生物质原料开发有效和可持续的生物柴油燃料的潜力。© 2021 化学工业协会和 John Wiley & Sons, Ltd 熔融催化剂最多可重复使用五个循环，而收率几乎没有降低。该研究证明了利用生物质原料开发有效和可持续的生物柴油燃料的潜力。© 2021 化学工业协会和 John Wiley & Sons, Ltd 熔融催化剂最多可重复使用五个循环，而收率几乎没有降低。该研究证明了利用生物质原料开发有效和可持续的生物柴油燃料的潜力。© 2021 化学工业协会和 John Wiley & Sons, Ltd