Abstract The focus of this work is to develop a reusable heterogeneous catalyst for the preparation of biodiesel. Among the potential raw materials, soybean dregs oil is extracted from waste soybean dregs, and limescale is used as a source of calcium oxide. The basic catalyst of mixed metal oxide of CaO and Al2O3 was synthesized by sol-gel method. The structure, composition and basicity of the synthesis catalyst were characterized by TG, XRD, BET, SEM-EDX, TEM-EDX, FTIR and CO2-TPD. The results indicate that the presence of the inert substance Ca5Al6O14 inhibits the accumulation of CaO and promotes its dispersion uniform. The FAEE yield reaches 92.6 % under the optimized conditions. Kinetic analysis shows that the experimental pattern conforms to a pseudo-first-order reaction kinetic model (R2 = 0.9674), and the activation energy required for the transesterification reaction is Ea = 62.36 KJ/mol. In addition, the catalyst shows high stability in this experiment, and no obvious performance loss is observed during the process of five cycles.

中文翻译：

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用于生物柴油生产的废水垢衍生可回收催化剂和豆渣油：分析和优化

摘要 这项工作的重点是开发一种可重复使用的多相催化剂，用于制备生物柴油。在潜在的原料中，豆渣油是从废豆渣中提取的，水垢是氧化钙的来源。采用溶胶-凝胶法合成了CaO和Al2O3混合金属氧化物碱性催化剂。通过TG、XRD、BET、SEM-EDX、TEM-EDX、FTIR和CO2-TPD对合成催化剂的结构、组成和碱度进行了表征。结果表明惰性物质Ca5Al6O14的存在抑制了CaO的积累并促进其分散均匀。在优化条件下FAEE产率达到92.6%。动力学分析表明，实验模式符合拟一级反应动力学模型（R2 = 0.9674），酯交换反应所需的活化能为Ea = 62.36 KJ/mol。此外，该催化剂在该实验中表现出较高的稳定性，在五个循环过程中未观察到明显的性能损失。