Improving the activity and stability of turtle shell-derived catalyst in alcoholysis of degraded vegetable oil: An experimental design approach

In the activation of a heterogeneous catalyst, manipulating certain variables can affect its morphology, active sites and porosity which determine the efficiency of a heterogeneous catalyst. In this work, a highly efficient heterogeneous catalyst was synthesized from a waste turtle shell, which is a novel waste material. Using the experimental design, the influence of three parameters: calcination temperature, calcination time and KOH loading on the catalyst efficiency was studied. The catalyst efficiency was measured by taking the average biodiesel yields in four re-use cycles. Among others, an optimum catalyst efficiency of 81.2% was obtained at a calcination temperature of 807 °C, calcination time of 196mins and KOH loading of 33%(w/w). The obtained Catalyst was very efficient since it possessed high catalytic property, including activity and selectivity, even after being used in four transesterification reactions.