Síntese do biodiesel de óleo de soja utilizando óxido de cálcio oriundo da concha de sururu impregnado com íon itérbio (3+)
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Data
2024-07-25
Autores
Gomes, Mirian Alves
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Universidade Federal do Espírito Santo
Resumo
The synthesis of biodiesel is carried out through transesterification reaction, using vegetable oils or animal fats, short-chain alcohols, in the presence of basic/acid catalysts, whether heterogeneous or homogeneous. Among heterogeneous catalysts, calcium oxide (CaO) shows promising results. In this study, calcium oxide obtained from sururu shell was impregnated with Yb3+ ions, via coprecipitation method. The catalysts were thermally activated by calcination at 900°C for 4 hours and evaluated for their catalytic potential in methyl biodiesel synthesis using soybean oil. Thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) were conducted to obtain catalyst characteristics and properties. Biodiesel yield was determined by proton nuclear magnetic resonance (1H NMR) and thin-layer chromatography (TLC). Central composite rotational design (CCRD) was employed to optimize reaction conditions. Results revealed that maximum efficiency was achieved at 80°C, with 5% catalyst and alcohol:oil ratio of 15:1, resulting in 87% conversion for CaO without Yb3+ and 85% for CaO with Yb3+, within just 1 hour. Modified CaO allowed for five cycles of biodiesel synthesis, with a 2.78% reduction in yield in the first catalytic cycle. Conversely, CaO without Yb3+ showed a significantly greater yield reduction, totaling 30.48%. The feasibility of reuse across multiple cycles was attributed to the robustness promoted by oxide impregnation, due to the low solubility of calcium oxide.
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Coprecipitação , Heterogêneo , Transesterificação