Ferryl Ion in the Photo-Fenton Process at Acidic pH: Occurrence, Fate, and Implications.
Ferryl Ion in the Photo-Fenton Process at Acidic pH: Occurrence, Fate, and Implications.
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DOI：
10.1021/acs.est.2c06373
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发表时间：
2023-03
影响因子：
11.4
通讯作者：
Guowei Deng;Zhen Wang;Jinxing Ma;Jin Jiang;Di He;Xianhui Li;Aleksandra Szczuka;Zhong Zhang
中科院分区：
文献类型：
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作者：
Guowei Deng;Zhen Wang;Jinxing Ma;Jin Jiang;Di He;Xianhui Li;Aleksandra Szczuka;Zhong Zhang
芬顿过程产生可以氧化天然和工程系统中的有机化合物的活性物质。虽然芬顿反应在酸性条件下产生羟基自由基（HO·）是有据可查的，但我们证明了在pH 2.8的UV/Fe（III）和UV/Fe（III）/H2 O2体系中，使用甲基苯基亚砜（PMSO）作为探针化合物产生铁酰离子（FeIVO 2+）。进一步阐明了FeIVO 2+是通过HO·氧化Fe（III）和[FeIII-OOH]2+的O-O均分解反应生成的。用激光闪光光解法测得HO·与Fe 3+反应的速率常数为4.41 × 107 M-1 s-1。由PMSO_2生成量拟合得到[Fe Ⅲ-OOH]~（2+）配合物热分解和光分解的速率常数和量子产率分别为1.4 × 10 ~（-2）s ~（-1）和0.3。在无H2 O2存在下，FeIVO 2+主要通过HO·和Fe 3+反应形成，而[FeIII-OOH]2+ O-O均裂对FeIVO 2+形成的相对贡献主要取决于[H2 O2]0/[Fe（III）]0的摩尔比、HO·清除水平以及UV/Fe（III）/H2 O2体系中的入射辐照度。因此，优化的动力学模型，开发通过将FeIVO 2+参与的反应到传统的photo-Fenton模型，它可以准确地预测在UV/Fe（III）和UV/Fe（III）/H2 O2系统中的Fe（II）的形成和污染物的衰减。我们的研究阐明了反应性氧化物种在光芬顿过程中的潜在形成机制，并强调了FeIVO 2+演变在调节铁循环和污染物减排中的作用。
Fenton processes produce reactive species that can oxidize organic compounds in natural and engineered systems. While it is well-documented that Fenton reactions produce hydroxyl radical (HO•) under acidic conditions, we demonstrated the generation of ferryl ion (FeIVO2+) in the UV/Fe(III) and UV/Fe(III)/H2O2 systems at pH 2.8 using methyl phenyl sulfoxide (PMSO) as the probe compound. Moreover, we clarified that FeIVO2+ is parallelly formed via the oxidation of Fe(III) by HO• and the O-O homolysis of [FeIII-OOH]2+ in the photo-Fenton process. The rate constant for the reaction between HO• and Fe3+ measured by laser flash photolysis was 4.41 × 107 M-1 s-1. The rate constant and quantum yield for thermal and photo O-O homolysis of [FeIII-OOH]2+ complex were 1.4 × 10-2 s-1 and 0.3, respectively, which were determined by fitting PMSO2 formation. While FeIVO2+ forms predominantly through the reaction between HO• and Fe3+ in the absence of H2O2, the relative contribution of [FeIII-OOH]2+ O-O homolysis to FeIVO2+ formation highly depends on the molar ratio of [H2O2]0/[Fe(III)]0, the level of HO• scavenging, and incident irradiance in the UV/Fe(III)/H2O2 system. Accordingly, an optimized kinetic model was developed by incorporating FeIVO2+-involved reactions into the conventional photo-Fenton model, which can accurately predict Fe(II) formation and contaminant decay in the UV/Fe(III) and UV/Fe(III)/H2O2 systems. Our study illuminated the underlying formation mechanism of reactive oxidative species in the photo-Fenton process and highlighted the role of FeIVO2+ evolution in modulating the iron cycle and pollutant abatement therein.