复合磁性MgAl水滑石制备及其酯交换性能的研究

使用共沉淀法制备磁性Fe_3O_4粒子,并以此为原料制备出Fe_3O_4/M g Al-LDH,将其焙烧产物Fe_3O_4/M g(Al)O作为微藻油脂和甲醇发生酯交换反应的催化剂,利用产物生物柴油产率作为评价催化剂的活性指标,探究其酯交换活性。通过TGDTG、XRD、SEM、EDS、TEM、N2吸附-脱附、VSM等表征手段对所制备样品进行表征。结果表明,Mg Al-LDH、Mg(Al)O在Fe_3O_4表面生长,并具有一定的磁响应能力。在反应时间为4 h、醇油物质的量比为13∶1的条件下,生物柴油产率高达90%。经过三次使用后,仍具有一定活性。在外磁场的作用下可完成催化剂与反应物的分离。

Preparation of compound magnetic Fe3O4/MgAl-layered double hydroxide and its application in biodiesel transesterification

Magnetic Fe₃O₄ was synthesized by chemical coprecipitation method, and used as a raw material for preparing Fe₃O₄/MgAl-LDH. The calcined Fe₃O₄/Mg(Al)O was taken as the catalyst for the transesterification of microalgae oil with methanol, and the biodiesel yield was used to evaluate the activity of the catalyst. Several instruments including TG-DTG, XRD, SEM, EDS, TEM, N₂ absorption-desorption and VSM were employed to characterize the catalysts. The results show that MgAl-LDH and Mg(Al)O are successfully formed on Fe₃O₄ particles which have a strong magnetic response. When the reaction time is 4 h and the methanol/oil mol ratio is 13:1, the biodiesel oil yield reaches to 90%. After using for three times the catalyst still has certain activity and can be easily separated and recycled.