Transesterification catalyzed by industrial waste-Lime mud doped with potassium fluoride and the kinetic calculation

Lime mud (LM), a solid waste from paper mill, is doped with potassium fluoride to prepare heterogeneous base transesterification catalyst. The catalyst is characterized by Hammett indicator method, Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The experimental results show that the basic strength of catalyst is the main reason for high catalytic activity. After doped with 20 wt.% KF and activated at 600 °C (KF/LM-600), the effects of catalyst addition percentage, molar ratio of methanol to oil, transesterification time, and transesterification temperature are concerned to examine the catalytic activity of KF/LM-600 and the reusability of KF/LM-600 is also investigated. Oil conversion of 99.09% could be achieved with catalyst addition percentage 5 wt.%, molar ratio of methanol to oil 12, transesterification time 2 h and transesterification temperature 64 °C. Furthermore, the kinetic parameters of transesterification catalyzed by KF/LM-600 are calculated.