Study on the Treatment of Paraquat-Containing Solution by H2O2/O3/UV Processes
This study was to investigate the treatment of paraquat-containing solutions by advanced oxidation processes (denoted by AOPs). The operation parameters conducted in semi-batch reactor were as follows: the effect of ozone dose, pH and H2O2 concentration on conversion of paraquat by adding O3, UV, O3/H2O2, UV/H2O2 and UV/O3/H2O2. Paraquat concentration: 10 ppm and 20 ppm, ozone dose: 45 g/hr and 105 g/hr, and H2O2 concentration: 0,07 g/l, 0.71 g/l and 1.127 g/l were tested.
In the first stage of pre-test, the purpose was to observe the decomposition of paraquat under various pH in order to compare the conversions by O3 and by O2, and to select the optimal pH in above AOPs.
The performances of AOPs for treating paraquat-containing solutions were found in sequence as follows: O3/H2O2, O3, UV/O3, UV/H2O2/O3, UV/H2O2 and UV. The process of O3/H2O2 not only could remove higher concentration of paraquat but also had to need a shorter residence time. The effect of parameters on the removal of paraquat by each AOPs were discussed.
The kinetics of AOPs in treatment of paraquat-containing solutions was confirmed by using half-life test. Except UV and UV/H2O2 processes nearing zero order, the apparent reaction order of O3, UV/O3, UV/O3/H2O2 and O3/H2O2 were obtained to be one.
Based on the removal and cost analysis, O3/H2O2 (O3 = 45 g/hr, H2O2 dose = 0.71 g/l) was the best process in treating paraquat solutions for the low energy and economic cost. As for the O3 and UV/O3 processes, we also recommended to be yours truly options.
Advisor:Jie-Chung Lou; Jimmy C. M. Kao; Ming-Shean Chou
School:National Sun Yat-Sen University
School Location:China - Taiwan
Source Type:Master's Thesis
Keywords:uv o3 h2o2
Date of Publication:06/23/2003