The synergetic action of UV in the ozonation of different organics
紫外光在臭氧降解不同有机物过程中的协同作用

Degradation of different organics such as p-chlorophenol(pCP), nitrobenzene(NB), acetic acid(ACA) and oxalic acid(OA) by O_3/UV were studied. The experimental results showed that synergetic action of UV and ozonation of organic was dependent on the property of organic itself. Under the experimental conditions, the TOC removal rate of pCP degraded by O_3/UV (59% in 30min) was lower than that of ozonation alone (66% in 30min); when the degraded organics were NB and OA, the combination UV with ozone could improve the degradation efficiencies obviously. For example, the TOC removal rates of NB and OA degraded by O_3/UV were 44% and 90%, respectively; and the enhancements of TOC removal rates reached 6% for NB and 33% for OA,respectively. O_3/UV could not improve the TOC removal rate compared with ozonation alone when ACA was degraded. Except for pCP, dissolved ozone could be detected in water during ozonation of the other three organics. The experimental results indicated that organics with UV adsorption and existed ozone oxidation in water were the necessary conditions for O_3/UV to improve the degradation efficiency. Except the activation of organics by UV, the by-product H_2O_2 was also an important factor for the enhancement of degradation efficiency of O_3/UV. The decomposition of dissolved ozone promoted by UV played possibly only an assistant role in this process.