Assessment of heterogeneous catalysts obtained from chicken egg shells and diatomite for biodiesel production

Abstract

The high global dependence on nonrenewable energies has prompted scientific studies aimed at developing new sources of renewable energy based on biofuel production. The biodiesel used in diesel engines has been one of the viable alternatives to mitigate the problems resulting from the use of fossil fuels. The industrial production of this biofuel uses basic homogeneous catalysts, but problems related to the high cost of purifying the product and waste generation, among others, are common. These complications have led to the development of a heterogeneous catalyst, which has proved to be a good option for biodiesel production. In this respect, the aim of the present study was to formulate and assess heterogeneous catalysts derived from chicken egg shells and diatomite for biodiesel production. Initially, the egg shell was calcined, forming CaO, followed by wet impregnation with diatomite via calcination at 800 °C for 240 min, producing the catalyst DiaCaO. The catalysts were characterized by XRD, FTIR, SEM, BET and XRF analyses, which confirmed the formation of catalytic solids based on the composition and chemical structure. In relation to biodiesel production, the CaO and DiaCaO catalysts exhibited similar yields, with the CaO precursor converting around 99% into biodiesel under favorable conditions (6:1 methanol:oil molar ratio, 2% catalyst and 2 h reaction time).

Keywords:

• Biodiesel
• heterogeneous catalysts
• chicken egg shell
• diatomite
• calcium oxide

Acknowledgments

The authors would like to thank the Universidade Federal do Rio Grande do Norte (UFRN), in particular the Graduate Chemical Engineering Program and CAPES, for the financial assistance received to carry out this research.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was funded by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.