The murumuru bark was used as a raw material for the synthesis of a catalyst through the carbonization process. The obtained biochar (BC) was functionalized with sulfonic groups under different temperature and sulfonation time conditions, to verify the influence of these variables on the activity of the catalyst produced, by their use in biodiesel production process through the methyl esterification of oleic acid. The study of the sulfonation time was performed through the evaluation of levels 1, 2, 4, 6 and 8 h, at a temperature of 200 °C. While the study of the temperature was done by the investigation of the levels 120, 140, 160, 180 and 200 °C, in the time of 4 h. The response to the catalytic activity of the sulfonated biochar was given through the measurements of surface acidity (SA) analysis and free fatty acid (FFA) conversion in the esterification reactions. For the study of the sulfonation time, the best results were found between 2 – 6 h, with a higher surface acidity value in 4 h (4.19 mmol H+ g-1), where the conversion was 98.5%. For the study of temperature, it was seen that high temperatures give high functionalization of the material. The catalyst with the highest surface acidity (4h) were highly efficient in their first reuse, with a conversion rate of 95.1%. This catalyst was characterized by Thermogravimetric Analysis (TG), Scanning Electron Microscopy (SEM), X-ray Fluorescence Dispersive Energy Spectroscopy (EDS) and Fourier Transform Infrared Spectroscopy (FT-IR). The results showed the promising viability for the use of murumuru bark as a raw material for the production of a solid catalytic acid in the process of biodiesel production through esterification.
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