In addition, the biodiesel phase after removal of the catalyst was measured
by ICP analysis to evaluate the leached Ca2+ ions. Fig. 8 also gave
the information of the concentration of Ca2+ ions leaching into the product
phase after each reaction cycle. As observation, high concentration of
leached Ca2+ ions was served in the first reaction cycle. The concentrations
of dissolved Ca2+ ions for the CaO and 30% RHA800-800 catalyst