|Title:||Oxidation of dimethyl phthalate with persulfate activated by UV, heating, and metal catalysts : a preliminary comparison of the kinetics and mechanisms of their reactions|
|Subject:||Hong Kong Polytechnic University -- Dissertations|
Phthalate esters -- Oxidation
Reaction mechanisms (Chemistry)
|Department:||Department of Civil and Structural Engineering|
|Pages:||vii, 79 leaves : ill. ; 30 cm.|
|Abstract:||It was hypothesized that the addition of Fe²⁺ or other transition metal ions, elevating temperature, or applying UV illumination in aqueous DMP+persulfate solution could enhance the oxidation of DMP by activated persulfate. In this study, the oxidation of dimethyl phthalate (DMP) with persulfate activated by UV, heating, Fe²⁺, and transition metal ions in aqueous solution was investigated in batch experiments. The experimental results showed that at room temperature, the addition of Fe²⁺ to the persulfate-water system significantly enhanced the oxidation of DMP. An optimal persulfate-to-Fe²⁺ molar ratio was found to be 5: 1 with about 25% of DMP removal. In the meantime, other transition metal ions used in this study (Ag⁺ , Ni²⁺, Sn²⁺ , Pd²⁺ , Mn²⁺) demonstrated no significant activation of persulfate in terms of DMP degradation. Increasing the temperature from 20 to 60 or 80 ℃ accelerated the oxidation rate of DMP, which achieved complete degradation after 120 min or 30 min, respectively. The complete degradation of DMP was also obtained with the persulfate activated by UVA and UVC illumination after 180 min and 20 min, respectively. A synergistic effect of UVA light illumination and Fe²⁺ addition on the activation of persulfate was confirmed by a complete degradation of DMP after 120 min. Furthermore, different activation methods were also compared in terms of TOC reduction and toxicity variation. The experimental results suggest that the oxidation of DMP with persulfate activated by UVC is the most energy-saving option to achieve the DMP degradation and mineralization. The oxidation of DMP with persulfate activated by UVA+Fe²⁺ could be a persulfate-saving option with the lowest molar ratio of persulfate to DMP and produced the final reaction solution with less toxicity comparatively.|
|Rights:||All rights reserved|
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