Optimization of microreactor-assisted transesterification for biodiesel production using bimetal zirconium-titanium oxide doped magnetic graphene oxide heterogeneous nanocatalyst

The application of novel heterogeneous catalyst materials with unique physicochemical properties for the production of biodiesel can increase the sustainability of the process. In this study, a novel heterogeneous nanocatalyst (NCT) was developed and improved using a microreactor for biodiesel production from used cooking oil (UCO). The NCT was developed based on double-layered bimetal titanium-zirconium oxide nanoparticles (NPs) incorporated over magnetic graphene oxide (ZrO₂-TiO₂@MGO) using a simple hydrothermal method. The physiochemical morphology of newly developed NCT materials of ZrO₂-TiO₂ NPs and ZrO₂-TiO₂@MGO was investigated using FESEM, FTIR, VSM, XRD, and EDX. The effects of several independent variables, including residence duration (60–180 s), oil/methanol molar ratio (1–3), and catalyst concentration (1–5 wt.%) on biodiesel production yield were optimized. The optimum reaction conditions in the microreactor-intensified transesterification process were the ZrO₂-TiO₂@MGO concentration of 4.75 wt.% (oil-based), reaction duration of 180 s, and oil/ methanol ratio of 2.33. The designed microreactor-assisted ZrO₂-TiO₂@MGO provided a conversion rate of 99.32%. Consequently, the results revealed that the microreactor effectively shortens the transesterification time while producing a high rate of biodiesel.