Recycled chicken eggshells after calcination have been used as a nonconventional heterogeneous catalyst for biodiesel synthesis from karanja oil from the pongam tree (Pongamia pinnata). The catalyst was characterized on X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and differential thermal analysis/thermogravimetric analysis (DTA/TGA). The formation of the calcium oxide phase was confirmed at 900°C after calcination. A high biodiesel yield of 95.0% and conversion of 97.4% was obtained at an 8:1 (alcohol/oil) molar ratio, 2.5 wt%catalyst, and 2.5 h reaction time at 65±°0.5C. The biodiesel conversion was determined by Fourier transform nuclear magnetic resonance (FTNMR) spectroscopy.
Sharma, Y. C., Singh, B., & Korstad, J. (2010). Application of an efficient nonconventional heterogeneous catalyst for biodiesel synthesis from Pongamia pinnata oil. Energy & Fuels, 24(5), 3223-3231.