Removal of dimethyl phthalate from water by UV–H2O2 process

This study aims to demonstrate the removal efficiency of dimethyl phthalate from water using the UV–H2O2 photooxidation process. Pure water samples, spiked with 20 ppm dimethyl phthalate (DMP) were treated by the combined effect of UV photolysis as well as hydrogen peroxide oxidation mechanisms. In the experiments, the concentration of hydrogen peroxide was varied from 34 to 136 ppm and a low-pressure mercury UV lamp of 100 mW power output was used to provide the necessary radiation. The effects of initial concentration of H2O2, UV exposure time, pH, and temperature were investigated. The results showed that about 60% of DMP were removed directly by activation caused by UV light radiation intensity after an exposure time of 1 h. However, the removal efficiency increased when the DMP-spiked water was dosed with H2O2 prior to irradiating with UV light (i.e., UV–H2O2). More than 98% of DMP was removed after 45 min when the UV-irradiated solution was dosed with 136 ppm of H2O2. The results also showed that lowering the pH and increasing the temperature enhanced the removal of DMP by UV–H2O2 process. Key words: ultraviolet light, hydrogen peroxide, hydroxyl radical, phthalates, UV–H2O2 process, advanced oxidation processes.