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论文类型：期刊论文

发表时间：2009-08-01

发表刊物：JOURNAL OF GEOCHEMICAL EXPLORATION

收录刊物：SCIE、EI

卷号：102

期号：2

页面范围：49-55

ISSN号：0375-6742

关键字：Fe(III)-HA complex; Photodegradation; Atrazine; Characterization

摘要：This study examined the effects of humic acids (HA) and Fe(III)-HA complex on the photodegradation of atrazine, one of the most widely used herbicides. It was shown that the photolysis of atrazine proceeded via first-order reaction kinetics and that atrazine photodegradation was inhibited by the presence of HA, whereas the rate for atrazine photolysis was promoted in solutions containing both HA and Fe(III). Interactions of Fe(III) with HA were characterized by SEM, EDX, UV-Vis and FTIR, revealing that Fe(III)-HA complex was formed by ligand exchange between oxygen groups of HA and Fe(III). Using fluorescence spectrometry the stability constant (K(c)) and the fraction of fluorophores available for complexation (f) were obtained as log K(c)=4.28 and f=74%. Photoformed Fe(II) by ligand-to-metal charge-transfer (LMCT) within the Fe(III)-HA complex was the most important factor involved in photolysis of atrazine, since Fe(II) was the reactant to generate hydroxyl radical. Thus, the rate of atrazine photodegradation in natural sunlit waters is dependent on both the amount of iron present and the interaction between HA and iron. (C) 2009 Elsevier B.V. All rights reserved.