Biodiesel Production by Esterification Reaction on K⁺ Modified MgAl-Hydrotalcites Catalysts

• Main Authors: Chen-Yang Zhang, Wen-Li Shao, Wei-Xia Zhou, Yang Liu, Yuan-Yuan Han, Yi Zheng, Yong-Jun Liu
• Format: Article
• Language: English
• Published: MDPI AG 2019-09-01
• Series: Catalysts
• Subjects: MgAl hydrotalcites; solid alkaline; biodiesel; K⁺ modified; ultrasonic aid
• Online Access: https://www.mdpi.com/2073-4344/9/9/742
• ISSN: 2073-4344

K⁺ modified hydrotalcites and its activity as a solid base catalyst for ultrasonic wave- assisted biodiesel conversion was investigated. The solid alkaline catalysts of the MgAl-hydrotalcites (HT) was prepared by co-precipitation and modified with K⁺ by impregnation. The influence of K⁺ incorporation on the performance of Mg-Al hydrotalcites catalysts was investigated by SmartLab X-ray powder diffractometer (XRD), infrared spectrum (IR), thermogravimetric-differential thermal analysis (TG−DTA), CO₂ temperature programmed desorption (CO₂-TPD), scanning electron microscopy (SEM), and N₂ adsorption−desorption isotherm (BET). The research discovered that K⁺ modified of double layered structure of MgAl-hydrotalcite resulted in a significant increase in catalytic activity in transesterification of rapeseed oil. It exhibited high catalytic activity that achieved a biodiesel yield of 99% when the reaction was conducted with 2 wt% catalysts, K⁺/HT load ratio of 6.25%, a methanol/rapeseed oil molar ratio of 12:1, and reaction at 60 °C over 1 h. The result showed that the K⁺ modified HT as a transesterification catalyst had the potency for biodiesel conversion. In addition, under the above reaction conditions, the biodiesel yield was up to 99.9% in only five minutes with ultrasonic aid.