The degradation of used cooking safflower oil aqueous solutions by photolysis, Fenton, and photo Fenton under solar light is reported. The processes were carried out in a photochemical reactor with recirculation. Operating variables such as, pH, oil concentration and molar ratio of [H2O2]:[oil] were investigated to test their effects on the treatment efficiency of Fenton process. Also the iron catalyzed decomposition of hydrogen peroxide in the solar photo Fenton reaction was studied under different experimental conditions. The degree of oil oxidation was monitored by the measurements of chemical oxygen demand (COD) analyses. It was found that at pH 2.6 and a molar ratio of [H2O2]:[oil] of 489:1 were more efficient for COD abatement. The experimental results showed that the sole effect of the solar irradiation (photolysis) aided to decrease ∼65% of COD at neutral pH in a reaction time period of 15 h; whereas a decrease of 47% and ∼90% of COD was obtained by Fenton and photo Fenton treatment, respectively, after a reaction time of 50 min. It was observed a decrease in the decomposition of H2O2 in the solar photo Fenton process, in subsequent additions of H2O2, and H2O2 + Fe2+.
Keywords: solar photo Fenton, solar photolysis, used safflower oil