Degradation of o-Toluidine by Fenton and photo-Fenton processes

• Main Authors: Chien-wei Chen, 陳建瑋
• Other Authors: Ming-Chun Lu
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/fmjmns

碩士 === 嘉南藥理科技大學 === 環境工程與科學系暨研究所 === 97 === Abstract o-Toluidine is a toxic pollutant which is widely used in many industries. However, it was found to be carcinogen, so it should be remove from wastewater before release into environment. In this research, the removal of o-toluidine by Fenton and photo-Fenton processes was investigated in depth. For Fenton process, the effects of initial pH, ferrous ion and hydrogen peroxide dosages on the o-toluidine were examined. The complete degradation of o-toluidine was (100%) found after 80 minutes when used 1 mM of Fe2+ and 5 mM of H2O2 at pH 3. In photo-Fenton process, the removal of o-Toluidine was investigated using Box-Behnken designs to find the key factors and optimum conditions. The effect of initial Fe2+ concentration, H2O2 concentration and number of UVA lamps were selected as a factor in Box-Behnken whereas o-toluidine removal and COD removal were considered as response functions. Results indicate that Fe2+ and H2O2 concentrations had positive effects on o-toluidine degradation whereas the amount of UVA lamps was not the key factor. The optimal number of UVA lamps, Fe2+ and H2O2 concentrations for the maximum o-toluidine removal (100% from prediction) and COD removal (74% from prediction) were 9, 1.2 mM and 8 mM, respectively. For the mineralization, o-toluidine and TOC removal efficiencies were examined and the results show that even o-toluidine could completely remove from the solution, however, TOC was still very high. This is probably due to the intermediates that might occur in the reaction. IC was used to identify intermediates in the reaction and the results reveal that during Fenton and photo-Fenton processes, there are formation of maleic acid and oxalic acid. In addition, the oxidation of o-toluidine was found to be a two-stage reaction. The first stage was under the influence of Fe2+/H2O2 reaction whereas the second stage was controlled by Fe3+/H2O2 reaction. Key words: Fenton process、Photo-Fenton process、Box-Behnken Design、o-Toluidine