الملخص الإنجليزي
Abstract:
Alarming environmental changes and the threat of natural fuel resource extinction are
concerning issues in human development. This has increased scientists’ efforts to phase out traditional
energy resources and move on to environmentally friendly biofuels. In this study, non-edible
castor oil was transesterified with methanol using a manganese-doped zinc oxide (Mn-doped ZnO)
nanocatalyst. A heterogeneous nanocatalyst was prepared by means of the the sonochemical method.
X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and transmission electron
microscopy (TEM) were used to characterize these nanocatalysts. The transesterification reaction
was studied under different temperature conditions, different ratios of methyl alcohol to castor
oil, and different amounts of the catalyst to identify optimum conditions in which the maximum
yield of biodiesel was produced. The maximum biodiesel yield (90.3%) was observed at 55 ◦C with
an oil-to-methanol ratio of 1:12, and with 1.2 g of nanocatalyst. The first-order kinetic model was
found to be the most suitable. Several thermodynamic parameters were also determined, such as
activation energy, enthalpy, and entropy. We found that this transesterification was an endergonic
and entropy-driven reaction. The results showed that the Mn-doped ZnO nanocatalyst could be
a suitable catalyst for the heterogeneous catalytic transesterification process, which is essential for
biodiesel production.
