Tran Hang Thi Minh, Pham Giang Hoang, Le Trong Van, Nguyen Ha Thanh, Hoang Trang Minh, Tran Son Van, Nguyen Khai Manh
Faculty of Environmental Sciences, University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai Road, 100000, Thanh Xuan, Hanoi, Vietnam.
Food Industries Research Institute, Ministry of Industry and Trade, Hanoi, Vietnam.
Environ Sci Pollut Res Int. 2025 Jul;32(31):18678-18693. doi: 10.1007/s11356-025-36731-7. Epub 2025 Jul 28.
Herbicide can cause pollution for the aquatic environment and limit the potential of using this source of water for drinking supply water. Thus, removal of this type of toxicant from water source is crucial in an integrated treatment system for drinking supply water from polluted surface water source. This paper aims to remove 2,4-dichlorophenoxyacetic acid (2,4-D), one type of herbicide, from water by a combined two-step Fenton reaction and ozonation in advanced oxidation process (AOP). Affecting factors of Fenton reaction (pH, contact time, dose of HO, dose of Fe) and ozone process (pH, dose of ozone, contact time) to 2,4-D removal efficiencies were investigated. The highest 2,4-D removal efficiency, achieving 100% for an initial concentration of 10 mg/L, was obtained under optimal conditions using the combined Fenton/ozone process. The conditions included (i) Fenton process, pH 3, HO dose of 0.3 mmol/L (mM/L), Fe dose of 0.03 mM/L, and a contact time of 1 h and (ii) ozone process, pH 8, ozone dose of 571.43 mg O/L, and a contact time of 1 h. The molar ratio of chemicals (H2O2 and Fe2+) to 2,4-D concentration; carbon content - C of 2,4D; and chemical oxygen demand (COD) were investigated to find out the most suitable conditions of Fenton/ozone reactions for 2,4-D reduction. Reduction mechanism of 2,4-D by two-step Fenton and ozone reaction was proposed through analyzing metabolites of degradation process. The Fenton process is responsible for organic chlorine radical reduction, while ozonation is for mineralization of metabolite degradation products.
除草剂会对水生环境造成污染，并限制将这种水源用于饮用水供应的可能性。因此，在处理受污染地表水水源的饮用水综合处理系统中，从水源中去除这类有毒物质至关重要。本文旨在通过高级氧化工艺（AOP）中两步芬顿反应和臭氧化相结合的方式从水中去除一种除草剂——2,4-二氯苯氧乙酸（2,4-D）。研究了芬顿反应（pH值、接触时间、过氧化氢剂量、铁剂量）和臭氧工艺（pH值、臭氧剂量、接触时间）对2,4-D去除效率的影响因素。在最佳条件下使用芬顿/臭氧联合工艺，对于初始浓度为10mg/L的2,4-D，获得了最高100%的去除效率。这些条件包括：（i）芬顿工艺，pH值为3，过氧化氢剂量为0.3mmol/L（毫摩尔/升），铁剂量为0.03mmol/L，接触时间为1小时；（ii）臭氧工艺，pH值为8，臭氧剂量为571.43mg O/L，接触时间为1小时。研究了化学物质（过氧化氢和亚铁离子）与2,4-D浓度的摩尔比、2,4-D的碳含量-C以及化学需氧量（COD），以找出芬顿/臭氧反应还原2,4-D的最合适条件。通过分析降解过程的代谢产物，提出了两步芬顿和臭氧反应对2,4-D的还原机理。芬顿工艺负责有机氯自由基的还原，而臭氧化则负责代谢产物降解产物的矿化。
