Parametric optimization by Taguchi L9 approach towards biodiesel production from restaurant waste oil using Fe-supported anthill catalyst

Abstract Restaurant waste oil is easily obtainable from local restaurants, while anthills grow widely in Oro, Nigeria. The anthills were first carbonized, then steam activated to prepare an inert, porous support capable of functional group adsorption. The support was then doped with Fe (II) using FeSO4 and the Fe/A catalyst was used in biodiesel synthesis from the RWO. L9 Taguchi OA was chosen to optimize the transesterification proves parameters comprising of catalyst concentration, methanol to oil ratio, reaction temperature and reaction time. The optimization revealed that methanol concentration does not affect the biodiesel yield significantly, while reaction time has the highest contribution. A biodiesel yield of 99.73% was attained at 60 °C for 1.5 h with 1.2% catalyst and 6:1 methanol:oil ratio. GC analysis showed the product to be rich in methyl esters. Fuel characterization tests show that the product has properties exceeding the standards set by ASTM. Kinetic studies show the process adheres to pseudo 1st order kinetics and has high reaction rate and frequency factor (A) with low EA, while the catalyst shows very efficient retention of functional groups, as evident from its reusability up to 7 times. Thus the process is energy and cost efficient, with a potential for commercialization.