A kinetic study of 3-chlorophenol enhanced hydroxyl radical generation during ozonation.
Hydroxyl (OH) radical is proposed as an important factor in the ozonation of water. In the present study, the enhancing effect of 3-chlorophenol on OH radical generation was mathematically evaluated using electron spin resonance (ESR)/spin-trapping technique. OH radical was trapped with a 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a stable adduct, DMPO-OH. The initial velocity of DMPO-OH generation in ozonated water containing 3-chlorophenol was quantitatively measured using a combined system of ESR spectroscopy with stopped-flow apparatus which was controlled by home-made software. The initial velocity of DMPO-OH generation increased as a function of the concentration of ozone and the more effectively of 3-chlorophenol concentration. The relation among ozone concentration, amount of 3-chlorophenol and the initial velocity (nu(0)) of DMPO-OH generation was mathematically analyzed and the following equation was obtained, nu(0) (10(-6)M/s)=[9.7 x [3-chlorophenol (10(-9)M)] + 0.0005]exp(57 x [ozone (10(-9)M)]). The equation fitted very well with the experimental results, and the correlation coefficient was larger than 0.99. The equation for the enhancing effect by 3-chlorophenol should provide useful information to optimize the condition in ozone treatment process of water containing phenolic pollutants.
Utsumi
Hideo
H
Department of Bio-function analysis, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan. utsumi@pch.phar.kyushu-u.ac.jp
Han
Youn-Hee
YH
Ichikawa
Kazuhiro
K
D002733:Chlorophenols / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000032:analysis / Q000737:chemistry*; D007700:Kinetics; D008962:Models, Theoretical; D016877:Oxidants / Q000032:analysis / Q000737:chemistry*; D010083:Oxidants, Photochemical / Q000737:chemistry*; D010126:Ozone / Q000737:chemistry*; D014872:Water Movements; D018508:Water Purification / Q000379:methods*
D002733:Chlorophenols; D016877:Oxidants; D010083:Oxidants, Photochemical; D017665:Hydroxyl Radical; D010126:Ozone; C030682:3-chlorophenol