These sources can substitute
fossil fuels in four distinct markets: power generation, heating
and cooling, transport fuels and rural/off-grid energy services [2].
In this sense, biodiesel is an alternative fuel that can be used
directly in commercial diesel engines. This biofuel has evident benefits
compared to fossil diesel fuel including enhanced biodegradation,
reduced toxicity and a lower emission profile [3]. Biodiesel is
generally produced by the transesterification of triglycerides from
vegetable oils and animals fats with alcohol in the presence of an
alkali or acid catalyst to form a mixture of fatty acid alkyl esters
and glycerol.
The major disadvantages of producing biodiesel are the high
cost of raw material and the subsequent purification process of
the product, which results in an expensive final product in comparison
to fossil diesel. Therefore, used cooking oils and fats offer a significant
alternative low-cost biodiesel feedstock. Additionally,
these raw materials can convert a problematic waste into an