| Endocrine Disrupting Chemicals (EDCs) is a typical and persistent toxic substance and has a very harmful effect on the all organisms, including the human beings, which has become an important issue on environmental pollution, especially referring to the security of drinking water. The removal ability for these compounds is limited in the current commen treatment mathods of coagulation, sedimentation and filtration. Therefore the new treatment methods of endorcrine disruptors with high efficiency need to be explored. In this paper, di-n-butyl phthalate (DBP), a kind of endocrine disrupter which generally exists in the drinking water source, was taken as the model pollutant. The removal efficiency of DBP by three processes, such as O3, O3/Ru/Al2O3and O3/MW/Mn/Al2O3were compared. And the influence on the DBP removal and its degradation characteristics under different conditions were evaluated. It was firstly proposed to remove the EDCs by the ozone-microwave induced catalytic oxidation techonology and the mechanism of heterogeneous catalytic ozonation and ozone-microwave induced catalytic oxidation were analyzed.The DBP could be oxidized quickly by ozone and the removal was affected by the substance concentration, initial reaction temperature, initial pH value, flux of mixed03and O2and concomitant organics. The substance concentration had a major influence and the removal efficiency was higher with the lower substance concentration when the other reaction conditions were same. The low temperature was in favor of the O3transfer in dynamic system, therefore, the efficiency in semi-continuous reaction increased with the decrease of initial temperature. The flux of mixed O3and O2should be controlled properly. The pH value is another important factor for DBP removal by ozonation. The removal efficiency was almost same in the neutral and acidic conditions, which was mainly the direct reaction between O3and DBP. With the increase of pH value, the removal efficiency presented the fast rising trend. However, the DBP removal by ozonation under the alkaline condition was seriously inhibited by tert butyl alcohol (TBA), which indicated that the indirect reaction of O3dominated in the alkaline condition.The catalysis of Ru/Al2O3could improve the DBP removal efficiency by ozone and the Ru/Al2O3catalyst prepared by ultrasonic immersion method has a higher catalytic activity. The oxidation efficiency of O3/Ru/Al2O3process is affected by catalyst immersion concentration, catalyst dosage, initial DBP concentration, ozone concentration, initial pH value, the existence of bicarbonate and TBA. In this study, the higher DBP removal was obtained with the immersion concentration of0.01464M, catalyst dosage of15g/L and higher initial pH value. The bicarbonate is a kind of accelerating agent in a low concentration, while it is an inhibitor with higher concentration. The inhibition of TBA to O3/Ru/Al2O3process was also evident, which indicated that in this catalytic ozonation process, ozone was decomposed to produce the hydroxyl radical by the catalysis of Ru/Al2O3and it followed the reaction mechanism of free radical.The oxidation efficiency of O3/MW/Mn/Al2O3process is affected by catalyst immersion concentration, microwave power, initial DBP concentration, microwave irradiation time, initial pH value, the existence of bicarbonate and TBA. The addition of ozone could enhance the capacity of microwave induced catalytic oxidation with the shortened microwave irradiation time and reaction time. In this study, the higher DBP removal was obtained with the immersion concentration of12.5%, microwave power of400W, microwave irradiation time of more than60s and higher initial pH value. The bicarbonate in low concentration could accelerate the oxidation process and reaction rate. The98%of removal efficiency was reached in reaction time of2min when pH value was11with extremely strong catalytic activity. The inhibition of TBA to03/MW/Mn/Al2O3process was apparent, which indicated that this oxidation process followed the reaction mechanism of free radical.TOC removal in both catalytic ozonation process of Ru/Al2O3and microwave induced catalytic ozonation process of O3/MW/Mn/Al2O3were all high. It was shown from the analysis results of intermediate product that there might be two attacking positions to DBP by hydroxyl radical, which were aliphatic chain and aromatic nucleus in DBP structure. Some aromatic products were formed after the aliphatic chain was attacked by hydroxyl radical, and then were broken up into fatty compounds through the benzene ring, such as formic acid, acetic acid and acetaldehyde. In another way, the aromatic nucleuses, except the5C and6C were attacked by hydroxyl radical and resulted in the formation of hydroxyl and hydroxyl intermediate products on aromatic nucleuses, which were further hydroxylated by hydroxyl radical. In addition, the two carbon atoms on the5C and6C could be attacked by the hydroxyl radical to form the carboxyl, a kind of intermediate with long chain. In the heterogeneous catalytic ozonation process, either the direct or the indirect oxidation of DBP by ozone accorded with the first-order kinetics model.It was found in this study that both catalytic ozonation process of Ru/Al2O3and microwave induced catalytic ozonation process of03/MW/Mn/Al2O3were simple and fast methods to form the hydroxyl radical orderly, which is a positive and environmental friendly oxidant and will play an important role in green chemistry, environmental protection and other related fields. This study has a vital significance in the research of advanced oxidation processes oriented by the hydroxyl radical.
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