Abstract
Calcined biowaste durian peel (BDP) contains 86% potassium element as the main compound and has successfully catalyzed the transesterification of palm oil to biodiesel at room temperature. The effect of catalyst weight, molar ratio of palm oil to methanol, reaction time, and rotational speed of the homogenizer device was investigated on biodiesel conversion and yield. The highest biodiesel conversion of 97.4 ± 0.3% was achieved using the following reaction conditions: a catalyst weight of 5 wt %, a molar ratio of palm oil to methanol of 1:15, a reaction time of 10 min, and a rotational speed of 6000 rpm. Unfortunately, calcined BDP could not hold its catalytic activity in the reusability study. The biodiesel conversion was decreased in the second cycle due to the decrease of both catalyst weight and concentration of potassium ions after the first cycle. However, the calcined BDP paired with a homogenizer device could produce biodiesel in a short reaction time and at room temperature.