State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China, 100084.
Advanced Water Management Centre, The University of Queensland, St Lucia, QLD, 4072, Australia.
Water Res. 2021 Feb 1;189:116629. doi: 10.1016/j.watres.2020.116629. Epub 2020 Nov 11.
Free nitrous acid (FNA)-based applications have been broadly adopted in the development of novel wastewater management technologies, but a basic understanding of the effect of the chemical properties of FNA on the elimination of micropollutants is still lacking. This study aims to comprehensively evaluate FNA-based elimination of sulfamethoxazole (SMX), which is a typical species of sulphonamide antibiotics. Batch experiments were conducted under different influencing factors to investigate the antibiotics elimination processes. We found that FNA showed specific efficacy on sulphonamides characterized by sulfonamide and aniline functional groups, such as SMX. SMX degradation was affected by the initial SMX concentration, FNA concentration and solution pH and described by d[SMX]/dt=-0.29e[SMX][FNA]. The cationic forms of SMX were more reactive towards FNA-based active components. Sulfonamide bond (S-N or C-S bonds) cleavage, nitrosubstitution, deamination and radical oxidation were proposed to be the relevant transformation pathways. The FNA-based technique was not effective for diminishing toxicity, but this process could strongly control antibacterial activity.
基于游离亚硝酸（FNA）的应用已广泛应用于新型废水管理技术的开发，但对于 FNA 的化学性质对消除微污染物的影响仍缺乏基本了解。本研究旨在全面评估 FNA 对磺胺甲恶唑（SMX）的消除作用，SMX 是磺胺类抗生素的典型代表。通过进行不同影响因素的批量实验来研究抗生素的消除过程。我们发现，FNA 对具有磺酰胺和苯胺官能团的磺胺类物质（如 SMX）表现出特殊的功效。SMX 的降解受初始 SMX 浓度、FNA 浓度和溶液 pH 值的影响，并由 d[SMX]/dt=-0.29e[SMX][FNA]描述。SMX 的阳离子形式对基于 FNA 的活性成分更具反应性。提出了磺酰胺键（S-N 或 C-S 键）断裂、亚硝化、脱氨和自由基氧化是相关的转化途径。基于 FNA 的技术对降低毒性效果不佳，但该过程可强烈控制抗菌活性。
