Composition-dependent regulation of 2,4,6-trichlorophenol dechlorination by NOM in a PAA/Fe(II) system

IF 12.5 1区工程技术 Q1 ENGINEERING, CHEMICAL

Chemical Engineering Journal Pub Date : 2026-10-06 DOI:10.1016/j.cej.2026.182829

Zhuoyu Li, Zeyu Zhao, Baiyu Yang, Zelin Niu, Chen He, Qianwei Li, Daoqing Liu, Qinghong Wang, Chunmao Chen, Jun Ma

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Abstract

Natural organic matter (NOM) is commonly regarded as a scavenger of reactive oxygen species (ROS) in advanced oxidation processes, although its redox-active moieties may also promote iron cycling. Here, the composition and concentration-dependent effects of NOM on the degradation and dechlorination of 2,4,6-trichlorophenol (2,4,6-TCP) were investigated in a peracetic acid (PAA)/Fe(II) process. At a concentration of 5 mg C/L, both humic acid (HA) and fulvic acid (FA) elevated 2,4,6-TCP removal within 4 h, and increased chloride release from 171 μM to 213 μM and 254 μM, respectively. However, further increasing the concentration of NOM to 25 mg C/L decreased the removal and dechlorination efficiencies of 2,4,6-TCP in HA based system, whereas FA maintained strong enhancement over a broader concentration range. FA exhibited a much higher electron-donating capacity (3.149 mmol e− gC−1), which was predominantly associated with its high total phenolic content and facilitated Fe(III) reduction and sustained PAA activation. Differently, the phenolic content in HA was lower (1.700 mmol GA gC−1), resulting in the limited Fe(II) restoration but larger scavenging effects under excessive dosages. Besides the typical reactive species of CH3C(O)OO· and Fe(IV) in Fe(II)/PAA system, the addition of NOM increased the contribution of ·OH to the degradation of 2,4,6-TCP. This transformation of reactive species was more pronounced in FA based system. ·OH was generated by the reaction of Fe(II) and organic peroxide radicals (ROO·), which originated from the oxidation of NOM in Fe(II)/PAA system. Molecular characterization further showed that NOM participated in oxidative transformation, accompanied by increased oxygen content and nominal oxidation state of carbon. Real water-derived dissolved organic matter from a natural lake and a biological contact oxidation tank had similar promotion effects on the dechlorination of 2,4,6-TCP, indicating the universality of enhancement of NOM on PAA/Fe(II) system. These results reveal that the important redox mediation of NOM on the stepwise dechlorination in NOM-containing waters.

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PAA/Fe（II）体系中NOM对2,4,6-三氯苯酚脱氯的组份依赖性调控

天然有机物（NOM）通常被认为是高级氧化过程中活性氧（ROS）的清除剂，尽管其氧化还原活性部分也可能促进铁循环。在过氧乙酸(PAA)/Fe（II）工艺中，研究了NOM的组成和浓度依赖性对2,4,6-三氯苯酚（2,4,6- tcp）降解和脱氯的影响。在浓度为5 mg C/L时，腐植酸（HA）和黄腐酸（FA）在4 h内提高了2,4,6- tcp的去除率，并使氯化物释放量分别从171 μM增加到213 μM和254 μM。然而，进一步增加NOM浓度至25 mg C/L会降低HA基体系中2,4,6- tcp的去除和脱氯效率，而FA在较宽的浓度范围内保持较强的增强作用。FA具有较高的给电子能力（3.149 mmol e−gC−1），这主要与其高总酚含量有关，有利于Fe（III）还原和持续的PAA活化。不同的是，HA中的酚类含量较低（1.700 mmol GA gC−1），导致铁（II）恢复有限，但在过量剂量下具有较大的清除作用。除了Fe(II)/PAA体系中典型的反应物质CH3C(O)OO·和Fe（IV）外，NOM的加入增加了·OH对2,4,6- tcp降解的贡献。在FA基体系中，这种反应物质的转化更为明显。·OH是由Fe（II）与有机过氧化物自由基（ROO·）反应生成的，而ROO·来源于Fe(II)/PAA体系中NOM的氧化。分子表征进一步表明，NOM参与了氧化转化，同时碳的氧含量和标称氧化态增加。天然湖泊和生物接触氧化池中真实水源溶出有机物对2,4,6- tcp脱氯的促进作用相似，说明NOM对PAA/Fe（II）体系的增强作用具有普遍性。这些结果表明，在含NOM水体中，NOM对逐步脱氯具有重要的氧化还原中介作用。

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来源期刊

Chemical Engineering Journal 工程技术-工程：化工

CiteScore

21.70

自引率

9.30%

发文量

6781

审稿时长

2.4 months

期刊介绍： The Chemical Engineering Journal is an international research journal that invites contributions of original and novel fundamental research. It aims to provide an international platform for presenting original fundamental research, interpretative reviews, and discussions on new developments in chemical engineering. The journal welcomes papers that describe novel theory and its practical application, as well as those that demonstrate the transfer of techniques from other disciplines. It also welcomes reports on carefully conducted experimental work that is soundly interpreted. The main focus of the journal is on original and rigorous research results that have broad significance. The Catalysis section within the Chemical Engineering Journal focuses specifically on Experimental and Theoretical studies in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. These studies have industrial impact on various sectors such as chemicals, energy, materials, foods, healthcare, and environmental protection.