Structural Influence on Photooxidative Degradation of Halogenated Phenols

Juretic, Daria; Puric, Jelena; Kusic, Hrvoje; Marin, Vedrana; Bozic, Ana Loncaric

Structural Influence on Photooxidative Degradation of Halogenated Phenols

2014

Juretic, Daria | Puric, Jelena | Kusic, Hrvoje | Marin, Vedrana | Bozic, Ana Loncaric

The influence of structure on degradation of five halogenated phenols (XPs) by UV/H₂O₂process was investigated. The combined influence of type or number of substituents and UV/H₂O₂process parameters (pH and [H₂O₂]) on the degradation kinetics of 2-fluorophenol (2-FP), 2-chlorophenol (2-CP), 2-bromophenol (2-BP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP) was studied using modified miscellaneous 3³full factorial design and response surface modeling (RSM). Studied XPs obey first-order degradation kinetics within the investigated range of process parameters. Determined degradation rate constants (kₒbₛ) were correlated with process and structural parameters by the quadratic polynomial models. Analysis of variance (ANOVA) demonstrated RSM models’ accuracy and showed that, in addition to pH and [H₂O₂], model terms related with the pollutant structure are highly influential. kₒbₛof mono-XPs follow the decreasing order 2-FP, 2-CP, and 2-BP, while CPs follow the decreasing order 2-CP, 2,4-DCP, and 2,4,6-TCP. Biodegradability (biochemical oxygen demand (BOD)₅/chemical oxygen demand (COD)) and toxicity (TU) were evaluated prior to the treatment and at the reference time intervals. The observed differences are correlated with the structural characteristics of studied XPs.

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