这项研究表明，在初始中性pH值下，紫外线A辐射的Fe III-硝酸三乙酸酯络合物可有效激活Oxone，从而诱导硫酸盐和羟基自由基（即SO 4 •和HO •）的生成。根据新出现的污染物Crotamiton的降解动力学，评估了溶液的pH值，次氮基三乙酸根：Fe III的摩尔比，Oxone和Fe III-次氮基三乙酸酯络合物的剂量等重要参数。结果表明，在初始周围环境条件下（例如pH 5.0-7.0），克罗米通的降解速度很快，其表观速率常数为0.0936-0.1287 min -1（基于紫外光通量的速率常数在0.48–0.66 J -1 cm 2）。另外，次氮基三乙酸酯∶Fe III的最佳摩尔比为1：1，较大的比例降低了克罗米通的降解速率，这是由于次氮基三乙酸酯对SO 4 •-的竞争作用。Oxone和Fe III-三三乙酸铁络合物的合适剂量分别确定为0.5 mM和0.1 mM。在给定的最佳条件下，在3.90 J cm -2的紫外线通量下，克罗米通的降解效率超过99％，优于通过活化S 2 O 8 2-获得的结果。和H 2 O 2。淬灭试验的结果（叔丁醇和2-丙醇作为清除剂）表明，SO 4 •-和HO •分别对巴豆胺的降解贡献了约65％和35％。此外，所鉴定的中间体包括羟基巴豆胺，二羟基巴豆酰胺，醛-巴豆酰胺，醛-二羟基-巴豆酰胺，N-乙基-2,3-二羟基-N-（邻甲苯基）丁酰胺，（E）-N-乙基-N-苯基丁-2-烯酰胺，2-（乙基氨基）苯甲醛和/或2-（邻甲苯基氨基）乙醛和（E）-N-乙基丁-2-烯酰胺。结果表明，SO 4 •-优先攻击克罗米通的酰胺和甲基。这项工作提供了对紫外线A辐射的Fe III-硝基三乙酸酯络合物活化Oxone的功效，自由基形成和机理的见解，为高级水处理提供了另一种方法。
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Oxone activation by UVA-irradiated FeIII-NTA complex: efficacy, radicals formation and mechanism on Crotamiton degradation
This study demonstrated an efficient activation of Oxone by ultraviolet light A-irradiated FeIII-nitrilotriacetate complex to induce the generation of sulfate and hydroxyl radicals (i.e., SO4•- and HO•) under initial neutral pH. The important parameters such as the solution pH, the molar ratio of nitrilotriacetate:FeIII, the dosages of Oxone and FeIII-nitrilotriacetate complex were evaluated in terms of the degradation kinetics of an emerging contaminant Crotamiton. The results indicated that fast degradation rates of crotamiton were achieved under initial circumneutral conditions (e.g., pH 5.0-7.0), with apparent rate constants at 0.0936–0.1287 min-1 (the ultraviolet light fluence-based rate constants at 0.48–0.66 J-1 cm2). In addition, the optimal molar ratio of nitrilotriacetate:FeIII was determined as 1:1, larger ratios decreased the degradation rate of crotamiton due to the competition effect of nitrilotriacetate on SO4•-. The suitable dosages of Oxone and FeIII-nitrilotriacetate complex were determined as 0.5 mM and 0.1 mM, respectively. Under the given optimal conditions, more than 99% degradation efficiency of crotamiton was achieved at an ultraviolet light fluence of 3.90 J cm-2, better than those results obtained by the activation of S2O82- and H2O2. The results of quenching tests (tert-butyl alcohol and 2-propanol as scavengers) suggested that SO4•- and HO• contributed ∼65% and 35% to the degradation of crotamiton, respectively. Furthermore, the identified intermediates includes hydroxy-crotamiton, dihydroxy-crotamiton, aldehyde-crotamiton, aldehyde-dihydroxy-crotamiton, N-ethyl-2,3-dihydroxy-N-(o-tolyl)butanamide, (E)-N-ethyl-N-phenylbut-2-enamide, 2-(ethylamino)benzaldehyde and/or 2-(o-tolylamino)acetaldehyde, and (E)-N-ethylbut-2-enamide. The results indicated that the SO4•- preferentially attacked on the amide and methyl groups of crotamiton. This work provided insight into the efficacy, radicals formation and mechanism on the activation of Oxone by ultraviolet light A-irradiated FeIII-nitrilotriacetate complex, offering an alternative approach for advanced water treatment.
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