Conversion of Au(Ⅲ)-polluted waste eggshell into functional CaO/Au nanocatalyst for biodiesel production

作者：Jiadi Liu; Minghuan Liu; Shaoyun Chen; Bingqing Wang; Jin Chen; Da-Peng Yang; Shangzhou Zhang^*; Wenxiao Du^*

来源：Green Energy & Environment, 2022, 7(02): 352-359.

Developing an environmental-friendly and highly active catalyst in transesterification for biodiesel production is of great importance for a more economic biodisel process. Herein, we reported that waste eggshells were used to adsorb Au(Ⅲ) in water and convert the Au(Ⅲ)-polluted eggshells into the functional nanocatalyst-Ca O/Au for the transesterification reaction between soybean oil and methanol to the preparation of biodiesel. By coupling of Ca O and Au nanoparticles, Ca O/Au nanoparticles showed superior catalytic activity for the transesterification reaction between soybean oil and methanol. An optimum performance was observed over Ca O/Au nanocomposites in a methanol-oil molar ratio at 12 : 1with catalyst content of 1.0 wt% at 70°C for 3 h. Besides, the catalytic activity of Ca O/Au nanocatalyst was almost unchanged after recycling for 5 times and the yield of biodiesel still kept at 88.9%. The proof-of concept study provided us a sustainable method for utilization of waste eggshells to remedy the metal ions-polluted wastewater and the synthesis of functional nanocomposite for biodiesel production, show great potential application of waste eggshell in adsorption and catalytic reactions.