Abstract
One of the objectives of this study was to delineate the effect of nitrate on the oxidation of di(2-ethylhexyl) phthalate (DEHP) by conducting bench-scale UV/H2O2 operations under a variety of UV doses and initial concentrations of H2O2 and . Also, this study evaluated the two processes, UV alone and UV/H2O2, for DEHP oxidation. DEHP separation and quantification were performed using liquid chromatography–electrospray ionization tandem mass spectrometry system (LC-ESI-MS/MS). It was found that the UV photolysis of H2O2 is a more effective method of DEHP oxidation than the direct UV photolysis. It was observed that the DEHP oxidation efficiency of about 85.0% or higher could be achieved at a UV dose of 800 mJ/cm2 with an initial H2O2 concentration of more than 30 mg/L in the absence of nitrate. Nitrate hindered the DEHP oxidation by acting as OH scavengers. The adverse effect by nitrate in the UV/H2O2 process was significantly greater than that in the UV oxidationalone, and its oxidation was almost reduced to half by nitrate under some operating condition. However, it is noted that the DEHP oxidation efficiency of more than 70% could be expected at a UV dose of 600 mJ/cm2 with an initial H2O2 concentration of 50 mg/L while considering the nitrate scavenging effect.
Notes
Challenges in Environmental Science and Engineering, CESE 2011 25–30 September 2011, Tainan City, Taiwan