Influence of Carbonation and Rehydration on Cao Derived From Calcining Chicken Eggshells in the Catalytic Process of Soybean Oil Transesterification

Abstract

CaO is the most used heterogeneous catalyst in transesterification reactions due to its high catalytic activity, low solubility in methanol, non-toxicity, and low cost. One of the greatest disadvantages of using CaO is its predisposition to react with H 2 O and CO 2 present in the atmosphere forming Ca(OH) 2 and CaCO 3, respectively. Therefore, the objective of this study is to investigate the catalytic capacity of the catalyst derived from calcined chicken eggshells on different days after calcination. The catalyst used was produced under a temperature of 800 °C during a period of 160 minutes. The catalytic solid was characterized on days 1, 2, 3, 4, and 15 after calcination by X-ray fluorescence (XRF), X-ray diffraction (XRD); thermogravimetric analysis (TGA); transmission electron microscopy (TEM); Brunauer, Emmett, and Teller isotherm (BET); and Hammett analysis techniques. The reaction occurred at a temperature of 65 °C, had a molar ratio of 12:1 alcohol/oil, used 6% catalyst, and was carried over a period of 3 hours. The results showed that the rehydration and carbonation processes did not significantly affect the CaO.