An Effective Regeneration Method for CaO/MgO Catalyst Used in Biodiesel Synthesis

Abstract

Six different regeneration methods were investigated for CaO/MgO catalysts used in biodiesel synthesis. Both the fresh and regenerated catalysts were evaluated in transesterification of methanol with rapeseed oil, and all catalysts were characterized by x-ray diffraction, Fourier transform infrared spectrometer, and CO₂-temperature programmed desorption. It is concluded that the most effective regeneration method is that the used catalysts are first washed with ethanol fully at ultrasonic vibration to remove the residual adsorbent, and then calcined at nitrogen atmosphere. With this method, the activity of the catalyst can be recovered completely, and an approximate yield to that of the fresh catalyst can be obtained after being recycled five times.

Keywords:

• CaO/MgO catalyst
• ethanol
• regeneration methods
• ultrasonic vibration