Iodinated X-ray contrast media (ICM) are widely used in medical imaging due to their stable properties, but they cannot be effectively removed in wastewater treatment plants (especially hospital wastewater). Therefore, ICM have been widely detected in aquatic environments and may gradually accumulate and cause adverse effects to the creatures. In this paper, the degradation characteristics of two most commonly detected ICM, iohexol and diatrizoate, by ultraviolet/persulfate (UV/PS) were investigated. UV/PS can effectively degrade both ICM, with pseudo-first-order rate constants (k_obs) of 0.3641 min⁻¹ for iohexol and 0.3511 min⁻¹ for diatrizoate, and SO₄·^₋ played a major role in UV/PS degradation of both ICM. The presence of I⁻, Cl⁻, Br⁻, humic acid (HA), and alkaline conditions inhibited the degradation efficiency of both ICM. Less I-DBPs were formed from iohexol at low PS and high Br⁻ concentrations, but from diatrizoate at high PS and Br⁻ concentrations. The degradation pathways of iohexol and diatrizoate in the UV/PS process were proposed separately according to the detected degradation intermediates. This study can provide an essential theoretical basis for the UV/PS degradation of the two ICM.

中文翻译：

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紫外线/过硫酸盐过程中碘海醇和泛影酸盐降解的比较研究：动力学、降解途径和碘化消毒副产物

碘化X射线造影剂（ICM）因其性质稳定而广泛应用于医学成像，但在废水处理厂（尤其是医院废水）中无法有效去除。因此，ICM在水生环境中广泛检出，并可能逐渐积累并对生物造成不利影响。本文研究了两种最常检测到的 ICM（碘海醇和泛影酸盐）通过紫外线/过硫酸盐 (UV/PS) 的降解特性。UV/PS 可以有效降解两种 ICM，碘海醇的伪一级速率常数 ( k _obs ) 为 0.3641 min ^{-1 ，泛影酸盐的伪一级速率常数 ( k obs ) 为 0.3511 min -1}，并且 SO ₄ · ^₋在 UV/PS 降解中发挥了主要作用两个 ICM 的。^{I -}、Cl ^-、Br ^-、腐殖酸（HA）和碱性条件的存在抑制了两种 ICM 的降解效率。^{在低 PS 和高 Br -}浓度下，由碘海醇形成的 I-DBP 较少，但在高 PS 和 Br ^-浓度下，由泛影酸盐形成的 I-DBP 较少。根据检测到的降解中间体，分别提出了UV/PS过程中碘海醇和泛影酸盐的降解途径。该研究可为两种ICM的UV/PS降解提供重要的理论基础。