Biodiesel Production Using K-Sr/CaO and CaO Catalysts Derived from Eggshells by Canola Oil Transesterification.

Eggshell calcination at 900 °C was used to produce CaO, which was afterward impregnated with K and Sr using KNO and SrCl·6HO precursors, diluted in methanol, to improve basicity, stability, and catalytic activity. The CaO doping with K-Sr affected the final catalyst's textural properties, alkalinity, and basic strength due to the K and Sr size and incorporation into the CaO lattice. SEM images with elemental mapping showed a uniform K and Sr distribution for the K-Sr/CaO catalyst.