Lee Doorae, Alyami Ibrahim, Zimila Hercilio, Arnold Robert G, Quanrud David M, Sáez A Eduardo
Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, USA.
Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, USA.
Water Res. 2025 Sep 1;283:123799. doi: 10.1016/j.watres.2025.123799. Epub 2025 May 9.
Both direct and indirect solar photolysis contribute to the in-situ attenuation of trace organic compounds (TOrCs) in surface waters, including those that are impacted by treated wastewater. In particular, the formation of singlet oxygen (O) from photosensitizers may play a role in the degradation of specific TOrCs. Quantification of the kinetics of photolytic processes is essential for anticipation of TOrC attenuation in sunlit waters. In this work, quantum yields for direct photolysis in sunlight and ultraviolet A light (290-400 nm), and second-order rate constants for TOrC reactions with O were determined for sixteen TOrCs that are ubiquitous in effluent-receiving surface waters. Six of the sixteen TOrCs (prednisone, dexamethasone, benzophenone, hydrocortisone, hydrochlorothiazide, and furosemide) were transformed via direct photolysis. Compounds that reacted readily with O included furosemide, propylparaben, and diltiazem. Second-order rate constants for reactions with O were determined using a kinetic model applied to a batch reactor and confirmed by measurement of kinetic solvent isotope effects (KSIE) in deuterated water (DO). A reactor model that combined direct and indirect photolysis was used to predict TOrC in chemically complex solutions containing natural organic matter (NOM) or effluent organic matter (EfOM), using the measured direct photolysis quantum yield and reaction rate constant with O.
直接和间接的太阳光光解作用都有助于地表水（包括那些受处理后废水影响的水体）中痕量有机化合物（TOrCs）的原位衰减。特别是，光敏剂产生单线态氧（O）可能在特定TOrCs的降解中起作用。光解过程动力学的量化对于预测阳光下水体中TOrC的衰减至关重要。在这项工作中，测定了16种在受纳废水的地表水中普遍存在的TOrCs在太阳光和紫外光A（290 - 400 nm）下直接光解的量子产率，以及TOrC与O反应的二级速率常数。16种TOrCs中的6种（泼尼松、地塞米松、二苯甲酮、氢化可的松、氢氯噻嗪和呋塞米）通过直接光解发生转化。与O容易反应的化合物包括呋塞米、对羟基苯甲酸丙酯和地尔硫䓬。使用应用于间歇式反应器的动力学模型测定了与O反应的二级速率常数，并通过在重水（DO）中测量动力学溶剂同位素效应（KSIE）进行了确认。结合直接和间接光解的反应器模型，利用测得的直接光解量子产率和与O的反应速率常数，预测了含有天然有机物（NOM）或出水有机物（EfOM）的化学复杂溶液中的TOrC。
