A study of the precipitation of cerium oxide synthesized from rare earth sources used as the catalyst for biodiesel production

Abstract

This work aimed to study the preparation of cerium oxide (CeO2) used as the catalyst for biodiesel production from palm oil. The precipitation method was used in the catalyst synthesis. The effects of oxalic concentrations and stirring rates in the precipitation process were investigated. Oxalic acid was added into cerium (Ce) in ethylenediaminetetraacetic acid solution to form Ce oxalate before the Ce oxalate was calcined to obtain CeO2. The results showed that oxalic concentrations and stirring rates slightly affect the morphology of CeO2. However, these parameters considerably affect the amount of basic sites of CeO2. The basicity of CeO2 plays the main role in catalyzing the transesterification reaction for biodiesel production. When CeO2 was used as the catalyst in biodiesel production from palm oil under operating conditions using a 5% catalyst, methanol-to-oil molar ratio of 30:1, reaction temperature of 150°C, 13.8 bars, and 3-h reaction time, CeO2 obtained from 3% oxalic concentration and 400 rpm stirring rates in the precipitation process provided the highest %FAME in the range of 93.9–94.2% since it had higher basicity. In addition, the decrease in surface area of CeO2 after the use was less severe than that of basicity due to catalyst deactivation.

Keywords

• precipitation
• cerium oxide
• rare earth
• biodiesel
• transesterification