Translated Abstract
Wastewater with chlorophenols is of extensive sources, quantity of emission, great toxicity, which can cause pollution to the environment. Chlorophenols are carcinogenic, teratogenic and mutagenic. They are very stable in the environment. They can be accumulated in organisms through the food chain, which are harmful to all biological individuals. More attention has been paid to the chlorophenol pollution which became the hot topic in the field of environmental protection.In this thesis, the effect for simulated wastewater of 4-chlorophenol (4-CP) was treated by dielectric barrier discharge (DBD) plasma. The impacts of various factors as well as the mechanisms and reaction kinetics were studied, and the main contents as follows:(1) The impacts of supply voltage, supply current and dielectric distance on effect of treatment were studied at atmospheric and oxygen pressure, with removal rate as evaluation index. The results indicated that the removal rate of 4-CP increased with increasing the voltage and current, decreasing the dielectric distance. On the conditions that supply voltage of 160V, supply current of 0.50A, dielectric distance of 5mm, initial concentration of 100mg•L-1and discharge time of 10mins, the removal rate of 4-CP can reach 100%. (2) The determination of H2O2, •OH and O3 induced by DBD were studied. And the contributions of these species to 4-CP degradation were investigated. The degradation intermediate products of 4-CP were analyzed by methods of gas chromatography-mass spectrometry (GC-MS) and Fourier transform infra-red spectrometry (FT-IR). The results revealed that •OH and H2O2 were the major factors on 4-CP degradation. The intermediate products during process of 4-CPdegradation were 4-chloro-1, 2-dihydroxybenzene, hydroquinone, benzoquinone, etc, which were broken down into CO2 and H2O after a series of reactions.(3) The primary study of the kinetics of 4-CP degradation by DBD plasma was deduced. Itwas found that the 4-CP degradation in aqueous solution fitted the first-order kinetics when the initial concentration was lower than 200 mg•L-1. As the concentration increased, it shifted to zero-order kinetics when the initial concentration was higher than 400 mg•L-1.(4)The effects of Fe2+ and Fe3+ on 4-CP degradation were alse studied. The results showed that the degradation rate of 4-CP can be greatly improved by adding Fe2+ and Fe3+, and the kinetics of 4-CP degradation still fitted first-order kinetics when the initial concentration was 100 mg•L-1.
Translated Keyword
[DBDLow temperature plasma4-CPDegradationMechanism]
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