The esterification reaction of oleic acid using heterogeneous catalysts can be a promising alternative for the production of biodiesel. This study proposed to obtain biodiesel from the esterification of oleic acid with the Zr-SBA-15 and SO42−/Zr-SBA-15 catalysts obtained by inserting Zr and subsequent sulphation of SBA-15 synthesized by the hydrothermal method. Zr-SBA-15 and SO42−/Zr-SBA-15 catalysts were initially synthesized by the wet impregnation method, followed by the sulphation process. The characterization of the catalysts was performed by: X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, nitrogen adsorption/desorption, scanning electron microscopy, energy-dispersive X-ray spectroscopy and acidity test, with the aim of identifying the structure, composition and verification of the presence of acidic sites. The characterization results indicated that SBA-15 preserved the ordered hexagonal structure, after the incorporation of Zr, with the presence of nanoparticles of this metal dispersed on the surface and inside the microporous and mesoporous channels of the Zr-SBA-15 catalyst. After sulphation, the amount of acid sites increased and the ordered structure was maintained. For the Zr-SBA-15 and SO42−/Zr-SBA-15 catalysts, there was the formation of tetragonal and monoclinic structures of ZrO2. The catalytic activity was evaluated by the esterification reaction of oleic acid via the methyl route. Biodiesel obtained with SO42−/Zr-SBA-15 presented physico-chemical properties within the standards specified by ANP Resolution N° 798/2019 and a better yield of 80.7%. SBA-15 did not show catalytic activity for the oleic acid esterification reaction under the reaction conditions of this study.
___________________________________________________________________resumo: O biodiesel é um combustível obtido a partir da transesterificação de óleos vegetais ou gorduras animais. Neste trabalho, o biodiesel foi obtido por meio da transesterificação do óleo de fritura residual (OFR), da gordura animal (sebo bovino) e de suas misturas em diferentes proporções. A reação aconteceu usando um álcool (metanol) na presença de um catalisador básico (KOH) na temperatura de 50°C por 60 minutos. O biodiesel foi caracterizado pelo índice de acidez, massa específica a 20°C, corrosividade ao cobre e viscosidade cinemática. As análises físico-químicas demonstram que biodiesel obtido 100% do sebo bovino foi o que apresentou melhores resultados em todos os requisitos analisados, o mesmo se enquadra na norma exigida pela ANP (Resolução nº45, 2014), o sebo que seria descartado e perdido apresenta baixo custo quando comparado a outras matérias primas para a obtenção do biodiesel, o óleo de fritura residual por sua vez também apresenta um baixo custo e pode ser utilizado para a produção de sabão e outros produtos derivados da glicerina, que seria previamente descartada. Embora sejam matérias primas de fácil acesso e que seu descarte de maneira incorreta pode gerar vários problemas ao meio ambiente, uma solução viável seria a produção de biodiesel, onde geraria renda e sustentabilidade.
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