| Summary: | 碩士 === 國立成功大學 === 環境工程學系碩博士班 === 97 === Persulfate is one of the oxidants used in of in-situ chemical oxidation (ISCO) of groundwater contamaintion. The oxidant may produce sulfate radical (SO4–•) and hydroxyl radical (OH•) with high oxidation potential in the remediation techniques. Although the oxidation potential for the chemical is high, the kinetics is very slow under typical environmental conditions. Therefore, the objective of this work was to investigate the feasibility of enhancing the reaction rates of persulfate for the oxidation of methyl tert-isobutyl ether using ultraviolet (UV) light.
In this study, 254 nm and 365 nm UV were used to activate persulfate for oxidizing MTBE at different pH values. MTBE was easily degraded by the persulfate/UV254 system. Within 50 mins, 53% of MTBE was mineralized in the persulfate/UV254 system. The concentration of persulfate was decreased by 40 %, while that of MTBE was reduced by 99.5% within 1 hour in the 254 nm UV system. A second-order kinetic model well described the reduction of MTBE in aqueous solution. At lower pH, higher kinetic rate was observed for MTBE reduction.
For the persufate/UV365system, MTBE was resistant to degrade. Within 1 hr of reaction, very minor amount of persulfate decomposed, and only 25% and 17% of MTBE was degraded and mineralized, respectively. Unlike that in the persulfate/UV254 system, the degradation of MTBE for this case followed a pseudo-first-order reaction.
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