Lee, Woorim; Marcotullio, Sandro; Yeom, Hoonsik; Son, Heejong; Kim, Tae-Hun; Lee, Yunho published the artcile< Reaction kinetics and degradation efficiency of halogenated methylparabens during ozonation and UV/H2O2 treatment of drinking water and wastewater effluent>, Recommanded Product: Methyl 3-chloro-4-hydroxybenzoate, the main research area is halogenated methylparaben degradation ozonation oxidative wastewater treatment; Hydroxyl radical; Micropollutant; Ozone; Paraben; UV/H(2)O(2).
This study investigated the reaction kinetics and degradation efficiency of methylparaben and its halogenated products (Cl-, Br-, Cl,Cl-, Br,Cl-, and Br,Br-methylparabens) during ozonation and UV254/H2O2 treatment. Second-order rate constants for reactions of the parabens with ozone and .OH were kO3 = 107 – 108 M-1 s-1 and [Formula Omitted] = (2.3 – 4.3)x 109 M-1 s-1 at pH 7. Species-specific kO3 values of the protonated and deprotonated parabens were closely related to phenol ring substituent effects via quant. structure-activity relationships with other substituted phenols. The UV photolysis rate of the parabens [kUV = (2.4 – 7.2)x 10-4 cm2 mJ-1] depended on the halogenation state of the paraben and solution pH, from which species-specific quantum yields were also determined In simulated treatments of drinking water and wastewater effluent, the parabens were efficiently eliminated during ozonation, requiring a specific ozone dose of > 0.26 gO3/gDOC for > 97% degradation During UV/H2O2 treatment with 10 mg L-1 H2O2, the degradation levels were > 90% at a UV fluence of 2000 mJ cm-2, except for Cl,Cl-methylparaben. Kinetic models based on the obtained reaction kinetic parameters could successfully predict the degradation levels of the parabens. Overall, ozonation and UV/H2O2 were effective in controlling parabens and their halogenated products during advanced water treatment.
Journal of Hazardous Materials published new progress about Absorptivity. 3964-57-6 belongs to class chlorides-buliding-blocks, and the molecular formula is C8H7ClO3, Recommanded Product: Methyl 3-chloro-4-hydroxybenzoate.
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