Abstract The most common reaction for biodiesel production is catalysed by acid, base or enzyme catalysts. When transesterification is completed, the reaction mixture contains various impurities such as soap, catalyst, free glycerol and alcohol that have to be removed to meet the biodiesel international standard specifications. In this work, biodiesel was produced by lipase catalysed transesterification from edible sunflower oil and methanol as substrates. The purification of crude biodiesel was carried out by decantation followed by ultrafiltration membrane technology. Four different membranes, polyethersulfone, polyacrylonitrile, polypropylene and regenerated cellulose were selected and used for biodiesel ultrafiltration. Based on permeate flux and glycerol content in the permeate membrane performance was evaluated. The obtained results showed that two out of four tested membranes have potential for biodiesel purification. Polyacrylonitrile membrane showed the best performance resulting in lowest glycerol content in permeate (0.006% (w/w)). Additionally, polyacrylonitrile membrane was successfully reused six times without significant loss of performance. Furthermore, the membrane blocking mechanisms were analysed for all membranes by Hermina’s model. Consequently, complete cake layer formation was identified as the most dominant blocking effect.

中文翻译：

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超滤法纯化脂肪酶催化酯交换产生的生物柴油：膜的选择和膜阻滞机制分析

摘要 生物柴油生产中最常见的反应是由酸、碱或酶催化剂催化。酯交换完成后，反应混合物中含有各种杂质，如肥皂、催化剂、游离甘油和醇，必须去除这些杂质才能符合生物柴油国际标准规范。在这项工作中，以食用葵花油和甲醇为底物，通过脂肪酶催化的酯交换反应生产生物柴油。粗生物柴油的纯化通过倾析和超滤膜技术进行。选择了四种不同的膜，聚醚砜、聚丙烯腈、聚丙烯和再生纤维素，用于生物柴油超滤。基于渗透通量和甘油含量对渗透膜性能进行评估。获得的结果表明，四分之二的测试膜具有生物柴油纯化的潜力。聚丙烯腈膜表现出最佳性能，导致渗透液中的甘油含量最低 (0.006% (w/w))。此外，聚丙烯腈膜成功地重复使用了六次，而没有显着的性能损失。此外，通过 Hermina 模型分析了所有膜的膜阻塞机制。因此，完全形成滤饼层被认为是最主要的阻塞效应。此外，通过 Hermina 模型分析了所有膜的膜阻塞机制。因此，完全形成滤饼层被认为是最主要的阻塞效应。此外，通过 Hermina 模型分析了所有膜的膜阻塞机制。因此，完全形成滤饼层被认为是最主要的阻塞效应。