Please cite this article as: Moradi G.R., Mohadesi M., Ghanbari M., Moradi M.J., Hosseini Sh., Davoodbeygi Y. Kinetic comparison of two basic heterogenous catalysts obtained from sustainable resources for transesterification of waste cooking oil. Biofuel Research Journal 6 (2015) 236-241. . Biofuel Research Journal 6 (2015) Alkaline earth metal oxides are appropriate catalysts for biodiesel production and among them, CaO and MgO are known for possessing the best efficiency. In this study, catalysts synthesized from economical and sustainable resources were used for biodiesel production. More specifically, waste mussel shells and demineralized (DM) water treatment precipitates as calcium and magnesium carbonate sources, were converted into calcium and magnesium oxides at temperatures above 900 C. Methanol and waste cooking oil were reacted in a 250 mL two-necked flask at 24:1 and 22.5:1 ratios in presence of 12 and 9.08 wt% of mussel shell-based and DM water treatment precipitates-based catalysts, respectively. The effects of temperature (328, 333, 338, 343 and 348 K) and time (1, 3, 5, 7 and 8 h) at a stirrer speed of 350 rpm on the conversion of the oil into biodiesel were investigated. The results obtained indicated a pseudo-first order kinetics for the transesterification reaction using both catalysts. The activation energies in the presence of the DM water treatment precipitates and mussel shell catalysts were measured at 77.09 and 79.83 kJ.mol -1 , respectively. Accordingly, the DM water treatment precipitates catalyst resulted in a faster reaction due to its lower activation energy value. Moreover, the catalysts were reused five times and the results obtained showed that the methanol-driven extraction of CaO contained in the DM water treatment precipitates catalyst was lower than the waste mussel shell catalyst proving the higher stability of the new heterogeneous catalyst i.e. the calcinated DM water treatment precipitates.© 2015 BRTeam. All rights reserved. Moradi et al. / Biofuel Research Journal 6 (2015) [236][237][238][239][240][241] Please cite this article as: Moradi G.R., Mohadesi M., Ghanbari M., Moradi M.J., Hosseini Sh., Davoodbeygi Y. Kinetic comparison of two basic heterogenous catalysts obtained from sustainable resources for transesterification of waste cooking oil. Biofuel Research Journal 6 (2015) 236-241..

Calcium oxide is one of the appropriate catalysts for biodiesel production. In this study, 40 wt. % CaO/Al 2 O 3 catalyst was used. Transesterification reaction was performed in optimal condition presented in the previous study (0.05 molar nitric acid and gelation temperature of 70 8C) in a 250 mL two-necked flask. All the experiments were carried out in the presence of soybean oil, methanol (methanol to oil molar ratio of 12:1), and catalyst concentration of 6 wt. %. Stirrer speed was set at 350 rpm. This study investigated the effects of reaction temperature and reaction time on produced biodiesel conversion. Methyl ester conversion changes in all temperatures and across different times indicated pseudo-first order kinetic, so, first, the observed rate constant was obtained at various temperatures. Then, observed activation energy of soybean oil methanolysis in the presence of CaO/ Al 2 O 3 catalyst was determined. The results show that maximum errors of model are in primary times because methanol is insoluble in soybean oil. At the other times and by biodiesel and glycerol production, there was increased solubility of methanol in oil. The methyl esters production rate is related to diffusion of methanol in oil film and reaction rate constants which are calculated these constants.

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