Using calcined waste fish bones as a green solid catalyst for biodiesel production from date seed oil

Abstract

Abstract Since biodiesels are widely considered more environmentally friendly and ecologically sustainable than fuels derived from petroleum – as well as producing greener energy at a lower price – this belief has encouraged the growth of the bio-economy. The primary objective of this work was to investigate the use of a novel non-edible feedstock obtained from date seed oil for the production of environmentally friendly biodiesel. This was achieved via the application of creative and different hydroxyapatite (HAPT) heterogeneous catalysts. These catalysts were obtained from discarded fish bones that were synthesized from dried fish bone and subjected to calcination at different temperatures. This study used several analytical methods, including transmission electron microscopy, Brunauer–Emmett–Teller analysis, X-ray diffraction (XRD), and thermogravimetric analysis, to investigate the properties of a cost-effective and environmentally sustainable catalyst derived from waste fish bones. HAPT is the key component of calcined catalysts, and this was confirmed using XRD analysis. The findings revealed that the transesterification activity was optimal when the catalyst was calcined at 900°C. Moreover, this produced a maximum yield of 89% fatty acid ethyl esters (FAMEs) when optimal reaction conditions were achieved (3-h reaction time, 9:1 ethanol/oil molar ratio, and catalyst amount of 4.5 wt%). Additionally, the catalyst was found to be durable and reusable throughout the biodiesel production process. The confirmation of FAME production was achieved using gas chromatography–mass spectrometry. This approach could facilitate the production of low-cost, environmentally friendly technology. Additionally, it was established that the characteristics of the biodiesel complied with ASTM D6571, an American fuel regulation. Green energy approaches can also be beneficial for the environment, which could ultimately improve societal and economic development for the biodiesel business on a larger scale.