Journal of Hazardous Materials 169 (2009) 772–779 Contents lists available at ScienceDirect Journal of Hazardous Materials journal homepage: www.elsevier.com/locate/jhazmat Degradation of atrazine photoinduced by Fe(III)–pyruvate complexes in the aqueous solution Changbo Zhang a,b , Lei Wang c , Gang Pan c , Feng Wu a,∗ , Nansheng Deng a , Gilles Mailhot b , Hana Mestankova b , Michele Bolte b a School of Resource and Environmental Science, Wuhan University, Wuhan 430079, PR China b Laboratoire de Photochimie Moléculaire et Macromoléculaire, UMR 6505 CNRS, Université Blaise Pascal de Clermont-Ferrand, F-63177 Aubière Cedex, France c State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China article info Article history: Received 19 November 2008 Received in revised form 17 February 2009 Accepted 5 April 2009 Available online 14 April 2009 Keywords: Fe(III) Pyruvate Atrazine Hydroxyl radical Photodegradation abstract The composition and photochemical properties of the Fe(III)–Pyr complexes in the aqueous solution was studied in this work. Fe(III) was complexed by Pyr in the ratio of 1:3. The photochemical processes occurred in the Fe(III)–Pyr system was studied in detail. Fe(II) was the main intermediate product. DMPO was used as scavenger to determine the active radicals, such as • OH, CO 3 •- , CO 2 •- ,H • and RCO 2 • by ESR. Photodegradation of atrazine induced by the photolysis of Fe(III)–Pyr was studied and the reaction kinetics fitted the first order reaction. Parameters such as pH, the initial concentrations of Fe(III), pyruvate (Pyr) and atrazine were all investigated. Photoproducts were detected by the LC–MS and the photodegradation scheme was proposed. • OH radical was the main pathway of atrazine degradation. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Carboxylic acids have received considerable attention as one of the most common dissolved organic compounds in natural environ- ment [1,2]. They were also considered to be one of the dominant classes of organic compounds found in the atmosphere in a vari- ety of phases [3–8]. They have been found in rainwater [9–12], snow and ice [13], on aerosol particles [14–17] and in the gas phase [18–20]. Pyruvic acid was one of the most abundant ketoacids presented in the atmosphere. Its presence has been reported in aerosols, rainwater and in the gas phase in urban atmosphere as well as in remote continental and marine areas. Andreae et al. [21] demonstrated that it was a product of the photochemical oxidation of natural organic compounds such as isoprene and cresols. It was expected to play a role in the precipitation acidity [22]. Available data indicated that pyruvic acid was lost in the gas phase mainly through photolysis. Mellouki and Mu [23] measured the reaction rate constant of • OH with pyruvic acid (CH 3 C(O)C(O)OH) in the gas phase. The value was k PA = (1.2 ± 0.4) × 10 -13 cm 3 molecule -1 s -1 at 298 K. They also detected • OH with a relative quantum yield of 5 ± 3% by the direct photolysis of pyruvic acid. However, the study of the ratio composition of the pyruvic acid complex with Fe(III) and ∗ Corresponding author. Tel.: +86 27 68778511; fax: +86 27 68778511. E-mail address: fengwu@whu.edu.cn (F. Wu). its detailed photolysis processes were unavailable from literature. In this work, we studied the ratio of Fe(III)–Pyr complexes and its photochemical properties. Atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5- triazine) was used as a model compound. It was a selective inside-absorbing herbicide which can be used in the fields of corn, sorghum, orchard and forest, controlling broad-leaf and grassy weeds [24]. It was not readily biodegradable and presented a rela- tively high persistence in soils and even reaches the groundwater. Its solubility in water was low (1.61 × 10 -4 M) and did not depend on pH [25]. Atrazine, like other herbicides of the S-triazine group, was barely oxidized by ozone [26]. Many methods have been developed to remove atrazine, including adsorption on activated carbon and advanced oxidation processes. These comprised both homogeneous and heterogeneous systems, for example the UV photolysis of hydrogen peroxide [27,28], the reaction of hydro- gen peroxide with ozone [29] or Fe(II) [30], ionizing radiation, ultrasound [31], photolysis by TiO 2 colloidal particles [32–35] and Fe(III)/oxalate systems [36]. There was no report that had been published with respect to the photodegradation of atrazine in the Fe(III)–Pyr systems. The aims of this study were as follows: (1) characterizing the physicochemical and photochemical properties of Fe(III)–Pyr com- plex; (2) determining the active oxygen species and proposing the photochemical processes that happened in the Fe(III)–Pyr system; (3) studying the photochemical degradation of atrazine induced by 0304-3894/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.jhazmat.2009.04.016