Reductive and oxidative degradation of iopamidol, iodinated X-ray contrast media, by Fe(III)-oxalate under UV and visible light treatment.
Reductive and oxidative degradation of iopamidol, iodinated X-ray contrast media, by Fe(III)-oxalate under UV and visible light treatment.
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DOI：
10.1016/j.watres.2014.09.009
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发表时间：
2014-12
期刊：
影响因子：
12.8
通讯作者：
Cen Zhao;Luis E. Arroyo-Mora;A. DeCaprio;V. Sharma;D. Dionysiou;K. O’Shea
中科院分区：
文献类型：
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作者：
Cen Zhao;Luis E. Arroyo-Mora;A. DeCaprio;V. Sharma;D. Dionysiou;K. O’Shea
碘帕醇广泛用作碘化X射线造影剂（ICM），在UV（350 nm）和可见光（450 nm）照射下，在Fe（III）-草酸盐光化学体系中易于降解。降解很好地模拟伪一级动力学。Fe（III）-草酸盐/H_2O_2/UV（350 nm）和Fe（III）-草酸盐/H_2O_2/可见光（450 nm）体系的羟自由基（自由基dotOH）产生速率分别为1.19 ± 0.12和0.30 ± 0.01 μM/min。对于Fe（III）-草酸盐/H2 O2/UV（350 nm）条件，羟基自由基（自由基dotOH）的稳态浓度为10.88 ± 1.13 × 10 - 14 M，对于Fe（III）-草酸盐/H2 O2/可见光（450 nm），为2.7 ± 0.1 × 10 - 14 M。在Fe（III）-草酸盐/H2 O2/UV（350 nm）条件下，超氧阴离子自由基（O2−radical dot）的产生速率为0.19 ± 0.02 μM/min，稳态浓度为5.43 ± 0.473 × 10− 10 M。使用液相色谱法结合Q-TOF/MS进行的详细产品研究表明，还原（多次脱卤）和氧化（芳环和侧链）均有助于降解途径。还原过程似乎是由二氧化碳阴离子自由基（CO2-自由基点）引发的，而氧化过程则与自由基点OH引发的反应途径一致。与大多数高级氧化过程不同，Fe（III）-草酸盐/H2 O2/光化学体系可以引发还原和氧化降解过程。所观察到的还原脱卤是卤代有机化合物的一种有吸引力的修复策略，因为该方法可以显著减少通常与氧化处理过程相关的有问题的消毒副产物的形成。
Iopamidol, widely employed as iodinated X-ray contrast media (ICM), is readily degraded in a Fe(III)-oxalate photochemical system under UV (350 nm) and visible light (450 nm) irradiation. The degradation is nicely modeled by pseudo first order kinetics. The rates of hydroxyl radical (radical dotOH) production for Fe(III)-oxalate/H2O2/UV (350 nm) and Fe(III)-oxalate/H2O2/visible (450 nm) systems were 1.19 ± 0.12 and 0.30 ± 0.01 μM/min, respectively. The steady-state concentration of hydroxyl radical (radical dotOH) for the Fe(III)-oxalate/H2O2/UV (350 nm) conditions was 10.88 ± 1.13 × 10−14M and 2.7 ± 0.1 × 10−14M for the Fe(III)-oxalate/H2O2/visible (450 nm). The rate of superoxide anion radical (O2−radical dot) production under Fe(III)-oxalate/H2O2/UV (350 nm) was 0.19 ± 0.02 μM/min with a steady-state concentration of 5.43 ± 0.473 × 10−10M. Detailed product studies using liquid chromatography coupled to Q-TOF/MS demonstrate both reduction (multiple dehalogenations) and oxidation (aromatic ring and side chains) contribute to the degradation pathways. The reduction processes appear to be initiated by the carbon dioxide anion radical (CO2−radical dot) while oxidation processes are consistent with radical dotOH initiated reaction pathways. Unlike most advanced oxidation processes the Fe(III)-oxalate/H2O2/photochemical system can initiate to both reductive and oxidative degradation processes. The observed reductive dehalogenation is an attractive remediation strategy for halogenated organic compounds as the process can dramatically reduce the formation of the problematic disinfection by-products often associated with oxidative treatment processes.