This study investigated the transformation of secondary amine pharmaceuticals in UV-C/NO₃⁻ and in nitrate-rich wastewater at 254 nm by taking diclofenac, diphenylamine, mefenamic acid and furosemide as probe compounds. The degradation of targeted compounds were positively related to nitrate concentration and mainly caused by the formation of peroxynitrite and related reactive nitrogen species (e.g., nitrogen oxide and nitrogen dioxide radicals). Major transformation products were identified to provide fundamental understanding of the selective oxidation of secondary amine with reactive nitrogen species. UV photolysis, hydroxyl radical oxidation, nitration and nitrosation processes were found to be the most significant transformation pathways. In case of diphenylamine, for which most of the identified intermediates were available as standard, the relative significance of each transformation route could be established, highlighting for the first time the important role of N-nitrosation processes in UV/NO₃⁻ treatment followed by the decomposition of the resulting N-nitroso compounds by an alpha hydroxylation mechanism. This specific transformation pathway was of concern because it constitutes the molecular basis of N-nitrosamine carcinogenicity and may contribute to the increase in effluent genotoxicity under UV-C treatment in addition to the formation of nitrophenols. Hydrogenocarbonate ions at concentration values higher than 300 mg/L appeared to be a protective specie against nitrosation processes due to the formation of carbamate adducts but H₂O₂ in UV-C/H₂O₂ could be responsible for an exacerbation of the N-nitrosation pathway due to an addition source of hydroxyl radical in the system. The occurrence of major transformation products of diclofenac was confirmed in nitrate-rich wastewater under UV-C treatment at pilot-scale operation.

本研究探讨在UV-C / NO仲胺药物的转化₃ ^-以双氯芬酸，二苯胺，甲芬那酸和速尿为探针化合物在254 nm的富含硝酸盐的废水中使用。目标化合物的降解与硝酸盐浓度呈正相关，并且主要由过氧亚硝酸盐的形成和相关的活性氮物质（例如，氮氧化物和二氧化氮自由基）引起。鉴定出主要的转化产物以提供对仲胺与反应性氮物种的选择性氧化的基本理解。发现紫外线光解，羟基自由基氧化，硝化和亚硝化过程是最重要的转化途径。如果使用二苯胺（大多数已鉴定的中间体作为标准品），则可以确定每种转化途径的相对重要性，₃ ^-处理，然后将得到的N-亚硝基化合物的由α羟基化机构的分解。该特定的转化途径令人关注，因为它构成了N-亚硝胺致癌性的分子基础，并且除了形成亚硝基苯酚外，还可能在UV-C处理下导致废水遗传毒性的增加。在浓度值碳酸氢离子高于300毫克/升似乎是对亚硝化过程的保护物种由于形成氨基甲酸酯加成物的除H ₂ ö ₂在UV-C / H ₂ ö ₂由于系统中存在羟基自由基，可能导致N-亚硝化途径的加剧。在中试规模操作的UV-C处理下，在富含硝酸盐的废水中确认了双氯芬酸的主要转化产物的存在。