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Overlooked enhancement of chloride ion on the transformation of reactive species in peroxymonosulfate/Fe(II)/NH2OH system
Water Research ( IF 11.4 ) Pub Date : 2021-02-25 , DOI: 10.1016/j.watres.2021.116973
Zhuo-Yu Li , Lu Wang , Yu-Lei Liu , Pei-Nan He , Xin Zhang , Jia Chen , Hai-Teng Gu , Hao-Chen Zhang , Jun Ma

Though hydroxylamine (NH2OH) is effective for accelerating pollutants degradation in Fenton and Fenton-like systems, the effect of anions simultaneously introduced by the hydroxylamine salts have always been ignored. Herein, effect of two commonly used hydroxylamine salts, hydroxylamine hydrochloride (NH2OH·HCl) and hydroxylamine sulfate [(NH2OH)2·H2SO4], for the degradation of dimethyl phthalate (DMP) in peroxymonosulfate (PMS)/Fe(II) system was comparatively investigated. Degradation efficiency of DMP with NH2OH·HCl was 1.6 times of that with same dosages of (NH2OH)2·H2SO4. SO4·, Fe(IV) and ·OH formed in the PMS/Fe(II)/NH2OH system, but ·OH was the major species for DMP degradation. Addition of Cl significantly improved the production of ·OH and Cl·, and the exposure dose of ·OH (CT·OH) was more than 10 times that of CTCl· as the concentration of Cl increased to 1 mM. Calculations based on branching ratios of Cl· and ·OH indicated that the reactions of Cl with SO4· and Cl· with H2O were not the only production sources of ·OH in the system. Further experiments with methyl phenyl sulfoxide (PMSO) as the probe indicated that Cl would facilitate the shift of reactive species from Fe(IV) to radicals (SO4· or ·OH) in the system. Both hydroxylation and nitration intermediate products were detected in the oxidation of DMP. Cl promoted the formation of hydroxylation intermediates and reduced the formation of nitration intermediates. This study revealed for the first time that Cl could shift reactive species from Fe(IV) to radicals in PMS/Fe(II) system, raising attention to the influence of the coexisting anions (especially Cl) for pollutants oxidation in iron-related oxidation processes.



中文翻译:

氯离子对过氧一硫酸盐/ Fe(II)/ NH 2 OH体系中反应性物种转化的增强作用

尽管羟胺(NH 2 OH)在加速Fenton和类似Fenton的系统中对加速污染物的降解是有效的,但是羟胺盐同时引入的阴离子的作用始终被忽略。本文中,两种常用的羟胺盐,即盐酸羟胺(NH 2 OH · HCl)和硫酸羟胺[[NH 2 OH)2 · H 2 SO 4 ]的作用,用于降解过氧单硫酸盐(PMS)中的邻苯二甲酸二甲酯(DMP)。 / Fe(II)系统进行了比较研究。NH 2 OH · HCl对DMP的降解效率是相同剂量(NH 2 OH)的1.6倍2 · H 2 SO 4。在PMS / Fe(II)/ NH 2 OH系统中形成了SO 4 ·,Fe(IV)和· OH ,但是· OH是DMP降解的主要物质。的Cl加成-显著提高了生产的· OH和Cl ·,和的曝光剂量· OH(CT · OH)为10倍以上的是CT的·例如Cl的浓度-增加至1mM。基于Cl ··的分支比的计算OH表示,Cl组成的反应-与SO 4 · -和Cl ·用H 2 ö不是唯一的生产源·系统中的OH。用甲基苯基亚砜(PMSO)作为探针进一步的实验表明,氯-将促进反应性物质的选自Fe(IV)的基团,以移位(SO 4 · -· OH)制得。在DMP的氧化过程中均检测到羟基化和硝化中间产物。氯-促进了羟基化中间体的形成并减少了硝化中间体的形成。这项研究揭示了首次氯-可能的活性物质从铁(IV)在PMS /铁自由基(II)系统转移,提高关注共存阴离子(特别是CI的影响- )中铁污染物氧化相关的氧化过程。

更新日期:2021-03-07
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