In this study, powdered waste chicken (Gallus domesticus) eggshells, which were used as a
raw calcium carbonate material, were calcined at 900 °C for 2 h in order to obtain calcium oxide
(CaO). It was then impregnated by 10% by weight (wt.%) of barium (Ba) using barium chloride
(BaCl2) precursor, and subsequently calcined at 900 °C for 4 h to yield a heterogeneous Ba/
CaO catalyst. The Ba/CaO catalysts were characterized by thermogravimetric analysis (TGA),
X-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectroscopy
(SEM-EDS), X-ray fluorescence spectrophotometer (XRF), Fourier-transform infrared
spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses. The prepared
catalysts were applied for the transesterification of canola oil with methanol under microwaveassisted
heating (300 W) to form fatty acid methyl esters (FAME). The FAME composition
was analyzed using gas chromatography with flame ionization detection (GC-FID). The
effects of the catalyst loading level, reaction time and methanol: canola oil molar ratio on the
FAME yield were evaluated independently (univariate analysis), while the catalyst reusability
was also investigated. The synthesized Ba/CaO catalyst showed a high catalytic performance
with a maximum biodiesel yield of 94% when using a 3 wt.% catalyst loading, 9:1 molar ratio
of methanol: canola oil for a 2 min of reaction time under 300 W microwave irradiation.
Furthermore, the catalyst exhibited good reusability with a biodiesel yield of more than 90%
after recycling for more than three cycles.