Removal of propham from water by using electro-Fenton technology: kinetics and mechanism.
The removal of a carbamate herbicide, propham, from aqueous solution has been carried out by the electro-Fenton process. Hydroxyl radical, a strong oxidizing agent, was generated catalytically and used for the oxidation of propham aqueous solutions. The degradation kinetics of propham evidenced a pseudo-first order degradation. The absolute rate constant of second order reaction kinetics between propham and ()OH was determined as (2.2+/-0.10)x10(9)m(-1)s(-1). The mineralization of propham was followed by the organic carbon (TOC) removal. The optimal Fe(3+) concentration was found as 0.5mM at 300 mA. The 94% of initial TOC of 0.25 mM propham solution was removed in 8h at the optimal conditions by using the cathode area to solution volume ratio of 3.33 d m(-1). The maximum mineralization current efficiency values were obtained at 60 mA in the presence of 0.5mM Fe(3+). During the electro-Fenton treatment, several degradation products were formed. These intermediates were identified by using high performance liquid chromatography, liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry and ion chromatography analysis. The identified by-products allowed proposing a pathway for the propham mineralization.
Ozcan
Ali
A
Anadolu University, Faculty of Science, Department of Chemistry, 26470 Eskişehir, Turkey.
Sahin
Yücel
Y
Oturan
Mehmet A
MA
D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D006540:Herbicides / Q000302:isolation & purification*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D048448:Phenylcarbamates / Q000302:isolation & purification*; D014867:Water / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
C045076:Fenton's reagent; D006540:Herbicides; D048448:Phenylcarbamates; D014867:Water; D006861:Hydrogen Peroxide; D007501:Iron; C100175:propham