Kinetics and characterization of transesterification of cottonseed oil to biodiesel using calcined clam shells as catalyst

ABSTRACT

The synthesis of biodiesel from cottonseed oil using heterogeneous calcined clam shells by transesterification was studied. The effects of the amount of catalyst and the oil-to-methanol ratio on the yield of the biodiesel produced were determined. A maximum yield of 84% biodiesel was obtained. Various characterization tests such as Fourier transform infrared spectroscopy (FT-IR), Gas Chromatography - Mass Spectrometry and Nuclear Magnetic Resonance Spectroscopy were carried out to ascertain the functional groups and compounds available in the product biodiesel obtained. The properties of the biodiesel using the calcined clamshell catalyst, such as density, viscosity, saponification value, iodine value and ester value, were estimated and compared with the American Society for Testing Materials standard values to determine the quality of the biodiesel produced. The yield of the biodiesel produced was modelled using response surface methodology, and contour regions were obtained. The surface morphology of the catalyst was studied using a scanning electron microscope. From the kinetics results obtained, the forward rate constant of the adsorption of methanol onto the catalyst surface was found to be very low (1.467 × 10⁻⁴), confirming that the kinetics of biodiesel production is limited by adsorption of methanol onto the active sites of the catalyst.

KEYWORDS:

• Transesterification
• cottonseed oil
• calcined clam shells
• biodiesel
• alternate energy

Disclosure statement

No potential conflict of interest was reported by the authors.