Synthesis and characterization of a heterogeneous catalyst from a mixture of waste animal teeth and bone for castor seed oil biodiesel production

The present study focused on the synthesis of heterogeneous catalyst from a mixture of waste animal teeth and bone through thermal method. The produced catalyst was used for castor seed oil (CO) biodiesel production. A different mixing ratio of teeth and bone was used with a calcination temperature range from 650 °C to 1250 °C with 100 °C increment for 3h calcination duration. Thermogravimetric analysis (TGA) for animal teeth and bone was performed to identify the common decomposition temperature range. The effect of calcination temperature on basicity of the catalyst and yield of biodiesel was studied for each teeth and bone mixing ratio. Maximum basicity of 6.12mmol HCl/g and biodiesel of 89.5wt% was obtained by mixing ratio of 25wt% teeth and 75wt% bone at calcination temperature of 1150 °C for 3h. The purity of the produced biodiesel in terms of mono fatty acid methyl esters (FAME) formation was found to be 92.6%. X-ray Diffraction (XRD), X-Ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FT-IR) and TGA was used to characterize the raw and produced catalyst. The maximum yield of FAME (89.5wt% with 92.6% purity) was obtained by 5wt% catalyst loading and 9:1 M ratio of methanol to castor seed oil at 60 °C reaction temperature for 3h. Compositional analysis of the produced CO FAME was performed by FT-IR, gas chromatography-mass spectroscopy (GC-MS) and nuclear magnetic resonance (NMR). The performance of the produced catalyst was also checked using its reusability for transesterification CO. Further, the physico-chemical properties including rheological properties of the produced CO FAME were characterized by ASTM methods to check its suitability as a liquid biofuel.