Yusuff A.S., Adeniyi O.D., Olutoye M.A. and Akpan U.G. (2018), Kinetic study of transesterification of waste frying oil to biodiesel using anthill-Ni-Co mixed oxide composite catalyst, Petroleum and Coal, Slovakia, 60(1):157-167, ISSN: 1337-7027.

Abstract

In this present study, the transesterification of waste frying oil with methanol over anthill-eggshell-Ni-Co mixed oxide catalyst was investigated. The composite catalyst was prepared via co-precipitation method and characterized by Brunauer-Emmett-Teller (BET), basicity, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) techniques prior to its activity study. The effects of reaction tempe-rature and reaction time on the catalytic reaction were investigated. The reaction order, activation energy and reaction mechanism based on Eley-Rideal principle were evaluated. From the BET analysis, it was revealed that calcination process has a positive effect on the textural properties of the catalyst. The high basicity exhibited by the catalyst implied that Lewis base sites are active centers for the catalytic reaction. From the XRD analysis, the active phases in the catalyst were determined to be calcium oxide (CaO), silica (SiO2), nickel oxide (NiO) and cobalt oxide (CoO). From the FTIR studies, the peak changes of the spectra obtained before and after calcination process corresponded to tem-perature effect. The obtained results showed that both reaction temperature and reaction time had significant influence on transesterification reaction. The reaction was first order with respect to triglyceride and second order with respect to methanol. The activation energy and collision factor were 23.99 kJ/mol and 1.62 x 106 M-1 min-1 respectively. The reaction mechanism agreed reasonably well with Eley-Rideal kinetic.