No abstract

The stable of natural diatomite supported by potassium hydroxide (KOH) as catalysts were synthesized for biodiesel production. A heterogeneous base catalyst prepared by impregnating KOH onto diatomite was also used to synthesize biodiesel from palm oil. All samples have been thoroughly characterized by Wavelength Dispersive X-ray Fluorescence (WDXRF), X-ray diffraction (XRD), N2 adsorption/desorption, Scanning electron microscopy (SEM), Energy dispersive spectrometer (EDS), and Temperature-programmed desorption of carbon dioxide (CO2-TPD). The XRD, XRF, and SEM results confi rm that adding KOH to diatomite results in structural change. The SiO2 and K2O phases form in the diatomite structural matrix during impregnation and the total basicity amount of this compound promotes the transesterifi cation process. A maximum fatty acid methyl ester (FAME) content of 84.56% was obtained. The reaction conditions were as follows: molar ratio of oil to methanol 1:9, catalyst loading 5 wt%, reaction time 2 h, and reaction temperature 75 °C. This work provides a possible new method for converting KOH from a homogeneous to a heterogeneous catalyst (Diatomite/KOH) that may show stable reusability, avoiding the separation and pollution problems in the environment.

This work presents the synthesis and characterization of mixed rare earths hydroxide heterogeneous catalyst. The catalysts were prepared by co-precipitation of mixed rare earths with NaOH at different pH (6, 7 and 12). The prepared catalysts were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDS). The XRF results showed that the catalyst composed of cerium (Ce), neodymium (Nd), lanthanum (La), praseodymium (Pr) and samarium (Sm) being predominant at pH up to 7. Particularly, cerium (Ce) was favorable precipitation at pH 7. This results were confirm by SEM-EDS. The Ce (OH)3 phase was clearly observed for the mixed rare earth catalyst precipitated at pH 7. The XRF, SEM-EDS and XRD results were consistency.