| Summary: | 碩士 === 國立成功大學 === 尖端材料國際碩士學位學程 === 105 === Through the years, the demand for renewable sources of energy increases significantly as we are facing serious problems with safety hazards, air and land pollution, global warming and many other ecological complications. Biodiesel is an alternative diesel fuel derived from animal fats or vegetable oils. It is purely biodegradable, non-toxic and sustainable.
Biodiesel is made from the process called transesterification wherein animal fats or vegetable oils (triglyceride) are mixed with alcohol, and with an aid of a catalyst, will produce biodiesel and glycerol. For this study, we focused our research on the catalyst, a heterogeneous basic catalyst to be specific. One of the drawbacks of using basic catalyst is the low biodiesel yield due to soap formation and lack of reusability due to serious problems of leaching. The goal was to develop a catalyst that will hinder soap formation and leaching during transesterification. We also wanted to determine the effects of single-phase versus two-phase oxides using CaxSr1-xO system.
In this study, we performed three various methods for catalyst synthesis – Co-Precipitation (CP), Solid State Sintering (SSS) and Polymer Complex Method (PCM). It was found out that PCM is the best method for synthesizing a high purity and homogeneous sample due to atoms mixed atomistically rather than just surface reactions for solid state sintering. PCM offers more purity than co-precipitation since the chelating agent catches the cations, which ensures random mixing and homogeneity.
Single phase Ca0.2Sr0.8O, exhibited the highest yield amongst all the catalysts. However, the two-phase system has stabilized the yield within its range. Leaching was also decreased within the two-phase region, as well as the particle size of the catalysts. It was also found out that Sr(OH)2 contributes significantly to the biodiesel conversion.
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