Abstract:

Sulfonamides (SAs) are one of the antibiotics with the highest frequency of detection and residual concentrations in natural aquatic environmental systems and sewage treatment systems. Peracetic acid (PAA), as a broad-spectrum biocide, has attracted much attention in recent years for the removal of organic pollutants owing to its oxidative properties and environmental friendliness. Compared to conventional Fenton and other inorganic oxidation treatments, PAA could release acetic acid and transform to sodium acetate after neutralization treatment, providing carbon sources for biochemical treatment processes and reducing the operational cost of SAs-containing wastewater treatment. Taking SAs as a typical target pollutant in the wastewater, this study reviews the removal effectiveness of PAA-based carbon source supplementation advanced oxidation processes (AOPs) for SAs by systematically summarizing and analyzing the AOPs with PAA activation in recent years. We compared various SAs removal effectiveness of different PAA activation methods, such as transition metals and carbon-based materials, and analyzed the cross-linking mechanism of the PAA activation methods, the operational parameters of the process, and reactive oxygen species (ROS). The mechanism of SAs degradation also has been revealed. The acetoxy radicals and peroxyacetyl radicals were identified as the basic active substances in the PAA-based carbon source supplementation AOPs. Furthermore, pH, PAA concentration, and co-existing substances could affect the ROS generation pathway in the system. In addition, SAs consisted mainly of five-member and six-member sulfonamides, and their degradation mechanisms were different. The degradation of five-membered sulfonamides primarily underwent four pathways: oxidation of the amino group on the aniline ring, hydroxyl substitution, S-N/S-C bond breaking, and N-centered radical coupling reaction. Except for abovementioned, the degradation mechanisms of six-membered sulfonamides also contained SO₂ extraction and a Smiles-type rearrangement. In the future, research of PAA-based carbon source supplementation AOPs would focus on the development of novel high-performance heterogeneous PAA activation method, and operational regulation and cost control of actual working conditions. This study could provide references and insights for the treatment of emerging contaminants in the aquatic environment using PAA-based carbon source supplementation AOPs.

Key words: sulfonamides, peracetic acid, AOPs, radicals, carbon source

摘要：

磺胺类抗生素（SAs）是自然水环境和污水处理系统中检出频次与残留浓度最高的抗生素之一。过氧乙酸（PAA）作为广谱性杀菌剂，因其氧化性强、环境友好等优势，其用于有机污染物降解成为研究热点之一。与传统H₂O₂基芬顿法等无机氧化法相比，PAA氧化反应生成乙酸，经中和后转化的乙酸钠可为后续生化工艺段提供优质碳源，有效降低含SAs废水的处理成本。该文对PAA基碳源补充型高级氧化法的研究进展与趋势进行了系统总结。以SAs作为典型水环境污染物，对近年来PAA基碳源补充型高级氧化工艺进行了系统总结分析，比较分析了其对各类水质背景中SAs的去除效能，并对过渡金属、碳基材料等多种PAA活化方式，工艺运行参数、活性氧物种（ROS）的交联作用机理以及SAs降解机制进行了剖析。研究发现，乙酰氧基自由基和乙酰过氧基自由基为PAA基高级氧化工艺中的基础活性物质，pH、PAA含量、共存物质等会不同程度上影响体系中ROS的生成路径。此外，磺胺类抗生素主要包括五元磺胺和六元磺胺，二者降解机理存在一定差异。五元磺胺降解主要依靠苯胺环上氨基氧化、羟基取代、S-N/S-C键断裂、N中心自由基偶联反应等4种途径；六元磺胺降解过程还包括SO₂脱除、斯迈尔斯重排等机制。在PAA基碳源补充型高级氧化工艺研究领域，新型高性能非均相PAA活化方式开发、实际工况的运行调控与成本控制等将成为未来研究热点。该文可为PAA基碳源补充型高级氧化工艺治理水环境新污染物的研究与应用方向提供参考。

关键词: 磺胺类抗生素, 过氧乙酸, 高级氧化工艺, 自由基, 碳源