Duan Jiebin, Cao Ying, Luo Xiaonan, Jiang Jin
Guangdong Basic Research Center of Excellence for Ecological Security and Green Development, Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, China.
Guangdong Basic Research Center of Excellence for Ecological Security and Green Development, Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, China.
Water Res. 2025 Oct 1;285:124146. doi: 10.1016/j.watres.2025.124146. Epub 2025 Jul 2.
This study systematically investigated the degradation of phenolic (phenol) and aromatic carboxylic (benzoic acid (BA)) compounds and formation of nitrogenous by-products in Fe(II)-activated peroxide systems with hydroxylamine (HA). Significant differences were observed between the peroxydisulfate (PDS)-based and hydrogen peroxide (HO)-based systems. The Fe(II)/PDS/HA system produced substantial yields of nitrosated and nitrated by-products, reaching 10-35 % for phenol and 2-17 % for BA. In contrast, the Fe(II)/HO/HA system showed minimal nitrosated and nitrated by-product formation, remaining below 1 %. Reactive species characterization identified Fe(IV), sulfate radical (SO), hydroxyl radical (•OH) and various reactive nitrogen species (RNS) including nitric oxide radical (•NO), nitrogen dioxide radical (•NO), and peroxynitrous acid (ONOOH) in the PDS system, while only •OH and •NO were detected in the HO system. The divergent nitrogenous by-product formation originated from distinct reaction mechanisms. In the PDS system, SO oxidized substrates to phenoxyl radicals that rapidly combined with RNS. In contrast, •OH addition in the HO system predominantly yielded hydroxylated intermediates with low reactivity toward RNS. Operational parameters including Fe(II) concentration, HA dosage, and pH significantly influenced both contaminant degradation and nitrogenous by-product formation. Notably, Cl promoted the formation of nitro(so) by-products in both PDS and HO systems through formation of nitrosyl and nitryl chlorides. This work presents the first direct evidence of HA-derived nitrogen incorporation into organic by-products via RNS-mediated transformation pathways in Fenton and Fenton-like systems. These findings highlight critical environmental implications for the application of HA-enhanced advanced oxidation processes (AOPs) in water and wastewater treatment, particularly concerning the potential formation of toxic nitrogenous transformation products.
本研究系统地研究了在含有羟胺（HA）的Fe（II）活化过氧化物体系中酚类（苯酚）和芳香族羧酸类（苯甲酸（BA））化合物的降解以及含氮副产物的形成。基于过二硫酸盐（PDS）的体系和基于过氧化氢（HO）的体系之间观察到显著差异。Fe（II）/PDS/HA体系产生了大量的亚硝化和硝化副产物，苯酚的产率达到10 - 35%，BA的产率达到2 - 17%。相比之下，Fe（II）/HO/HA体系显示出极少的亚硝化和硝化副产物形成，低于1%。活性物种表征确定了PDS体系中的Fe（IV）、硫酸根自由基（SO）、羟基自由基（•OH）以及包括一氧化氮自由基（•NO）、二氧化氮自由基（•NO₂）和过氧亚硝酸（ONOOH）在内的各种活性氮物种（RNS），而在HO体系中仅检测到•OH和•NO。含氮副产物形成的差异源于不同的反应机制。在PDS体系中，SO将底物氧化为苯氧基自由基，其迅速与RNS结合。相反，HO体系中•OH的加成主要产生对RNS反应性较低的羟基化中间体。包括Fe（II）浓度、HA用量和pH在内的操作参数显著影响污染物降解和含氮副产物的形成。值得注意的是，Cl通过形成亚硝酰氯和硝酰氯促进了PDS和HO体系中硝基（亚硝基）副产物的形成。这项工作首次直接证明了在芬顿和类芬顿体系中，HA衍生的氮通过RNS介导的转化途径掺入有机副产物中。这些发现突出了HA强化高级氧化工艺（AOPs）在水和废水处理应用中的关键环境影响，特别是关于有毒含氮转化产物的潜在形成。
