Abstract In this work, a green solid acid catalyst derived from the waste material of the angel wing shell (AWS) was synthesized using a two-step method: calcination followed by sulfonation. The calcined angel wing shell (CAWS) was supported with varied concentrations of sulphuric acid to obtain an optimum high acidity level of the catalyst. The CaO-based calcined angel wing shell sulphated (CAWS-(x)SO4) catalysts, where x = sulphuric acid concentration, were analysed using X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, temperature programmed desorption of carbon dioxide and ammonia, BET surface area, and scanning electron microscope. The specific surface area, pore volume, and pore diameter of the CAWS was increased significantly after being sulphated at the optimum sulphuric acid concentration; whereas, the CAWS-(7) SO4 showed the highest total amount of acidity (4726 μmol/g). The optimal FAME conversion (98%) from the PFAD was acquired at the reaction temperature of 80 °C, 15:1 MeOH:PFAD molar ratio and 5 wt% catalyst loading for a 3 h reaction time. The CAWS-(7)SO4 catalyst was reused two times with a high FAME yield without further treatment under optimized reaction conditions. The use of the AWS for the synthesis of catalysts has enormous potential for biodiesel production from high FFA oils due to its lower production cost, abundant availability and high catalytic activity.

中文翻译：

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使用由废天使翼壳 (Cyrtopleura costata) 合成的双功能催化剂将棕榈脂肪酸馏出物 (PFAD) 酯化为生物柴油

摘要 在这项工作中，采用两步法合成了一种来源于天使翼壳 (AWS) 废料的绿色固体酸催化剂：煅烧和磺化。用不同浓度的硫酸负载煅烧天使翼壳 (CAWS) 以获得催化剂的最佳高酸度水平。使用 X 射线衍射光谱、傅里叶变换红外光谱、二氧化碳和氨的程序升温脱附、BET 分析基于 CaO 的煅烧天使翼壳硫酸化 (CAWS-(x)SO4) 催化剂，其中 x = 硫酸浓度表面积和扫描电子显微镜。在最佳硫酸浓度下硫酸化后，CAWS的比表面积、孔容和孔径均显着增加；然而，CAWS-(7) SO4 显示出最高的酸度总量 (4726 μmol/g)。PFAD 的最佳 FAME 转化率 (98%) 是在 80 °C 的反应温度、15:1 MeOH:PFAD 摩尔比和 5 wt% 催化剂负载下获得 3 小时的反应时间。在优化的反应条件下，CAWS-(7)SO4 催化剂可重复使用两次，FAME 产率高，无需进一步处理。使用 AWS 合成催化剂具有从高 FFA 油生产生物柴油的巨大潜力，因为它具有较低的生产成本、丰富的可用性和高催化活性。在优化的反应条件下，CAWS-(7)SO4 催化剂可重复使用两次，FAME 产率高，无需进一步处理。使用 AWS 合成催化剂具有从高 FFA 油生产生物柴油的巨大潜力，因为它具有较低的生产成本、丰富的可用性和高催化活性。在优化的反应条件下，CAWS-(7)SO4 催化剂可重复使用两次，FAME 产率高，无需进一步处理。使用 AWS 合成催化剂具有从高 FFA 油生产生物柴油的巨大潜力，因为它具有较低的生产成本、丰富的可用性和高催化活性。