A new and efficient procedure for removing calcium soaps in biodiesel obtained using CaO as a heterogeneous catalyst

► The raw biodiesel obtained by using CaO as catalyst cannot be used as biofuel. ► It contains a large concentration of Ca cations and it requires an efficient procedure to remove Ca. ► A new procedure has been developed that allows the cleansing of the raw biodiesel by a simple water washing step. ► The procedure consists of incorporating Na2CO3 to the initial CaO-oil-methanol reaction mixture.