Preparation and Utilization of Hydroxyapatite-Supported Na and CaO–CeO2 Catalysts for Biodiesel Production Using Vegetable Oil Deodorization Distillate as Raw Material.

The study aimed to synthesize the hydroxyapatite (HAp), Na/HAp, and CaOCeO2/HAp materials, which were carried out using constant pH coprecipitation and wet impregnation methods and subsequently applied in the production of biodiesel using a by-product as a raw material. First, the HAp material was synthesized, and later there was the conventional impregnation by moisture to form the materials Na/HAp and CaOCeO2/HAp. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption and desorption, infrared spectral analysis (FT-IR), thermogravimetric analysis (TG), and morphology. The results showed that the residual lipid feedstock (vegetable oil deodorization distillate—VODD) that was used in the transesterification reactions for conversion into methyl esters (biodiesel) to determine the catalytic activity of the HAp, Na/HAp, CaOCeO2/ HAp it was shown that the HAp catalyst was not efficient in the complete transesterification of the starting materials. In this way, this catalyst remained with low activity, since the conversion to methyl esters reached 66% and, therefore, proved to be not a suitable catalyst for the transesterification reaction. On the other hand, the catalyst significantly improved its activity when HAp was impregnated with NaNO3 and CaOCeO2. The use of CaOCeO2/HAp in the transesterification of VODD was the catalyst that presented the best quality of catalytic activity (~ 99%) superior in relation to the Na/HAp catalyst. Thus, the CaOCeO2/HAp catalyst was selected as the most active catalyst in the transesterification reaction using VODD as raw material, and further tests were performed in order to optimize the process conditions. Therefore, an experimental design (design composed of face-centered 22 and center points) was carried out and the analysis of the results revealed that the formation of methyl esters (biodiesel) (> 95%) was strongly influenced by the temperature variable with a confidence level of 95%. Thus, confirming that the chemical catalyst was efficient to form the main esters of fatty acids even using a residual lipid raw material. [ABSTRACT FROM AUTHOR]