An important property of the heterogeneous catalyst is the reusability.
The CaO and 30% RHA800-800 catalyst were repeated eight times under their optimum reaction conditions.
Fig. 8 indicated that the CaO showed poorer stability (after 8 consecutive cycles, the biodiesel yield dropped to 55%). Although the catalytic activity of the 30% RHA800-800 catalyst was lower than that of the CaO, little deactivation could be found up to 8 consecutive cycles (after 8 consecutive cycles, the biodiesel yield was still above 80%).