With the rapid development of international economy, the
global energy supply has become more and more strained. However, the problems confronting us are worldwide energy shortages
and rising energy prices due to the continuous consumption of nonrenewable traditional fossil fuels. In the past decades, scientists
have spared no effort to explore for new replacements of energy
sources. Results found that the waste cooking oils (WCOs), including inedible vegetable oils or animal fats [1–5], could be used as
feedstock for the synthesis of biodiesel because of its low price
and abundant source, which had attracted worldwide attentions to
employ biodiesel as the alternative of traditional fossil fuels [6–9]