Síntese de catalisador heterogêneo magnético básico aplicado no processo de produção de biodiesel

Abstract

This research focus on the development of a basic magnetic heterogeneous catalyst, using, for the first time, NaAlO2 as an active species supported in a magnetic material, CuFe2O4, being highly stable and effective to produce value-added products, such as biodiesel. With this purpose, a series of catalysts (x-NaAlO2/CuFe2O4) have been successfully synthesized by means of conventional and low-cost methods, such as coprecipitation and impregnation, each one being assessed in the soybean oil transesterification reaction. The features of the 25-NaAlO2/CuFe2O4 catalyst with the higher performance have been elucidated through techniques such as basicity by acid-base titration method, XRD, FTIR, SEM, EDS, TG/DTG and VSM. To optimize the biodiesel’s ester content, the face-centered central composite design (FCCD), integrated with the response surface methodology (RSM), was employed to assess the effect of the following aspects on the process: reaction temperature, MeOH:oil molar ratio, catalyst dosage and reaction time. The regression model presented R2 = 0.9394 and experimentally reached a maximum ester content of 95.9% (relative error < 5%) attributed to the biodiesel attained under the following optimal reaction conditions: temperature of 95 °C, MeOH:oil molar ratio of 13:1, catalyst dosage of 8% and time of 60 min. The NaAlO2/CuFe2O4 catalyst presented a stable catalytic performance during four transesterification cycles (>90.0%) and an efficient magnetic property for the catalyst separation and recovery process (Ms = 23.62 emu g-1). The results showed that the biodiesel’s physicochemical properties were in compliance with ASTM D6751 standard. Finally, this extensive study reveals the basic magnetic heterogeneous catalyst NaAlO2/CuFe2O4 as a practical and promising alternative to produce a sustainable biofuel.