Abstract:The widespread use of pharmaceuticals and personal care products (PPCPs, including antidepressants, etc.) has raised significant concerns about the impact on aquatic ecosystems and human health. Among these, antidepressants are particularly concerning due to their frequent detection, persistence in the environment, and potential harmful effects. Consequently, antidepressants have become a major research focus within the study of PPCPs. In recent years, various techniques have been proposed to address the challenge of controlling and removing antidepressant contaminants from water bodies. However, many of these methods face significant limitations. This review systematically examines the environmental fate and ecotoxicity of antidepressants in aquatic environments, highlighting the challenges posed by conventional water treatment methods, as well as the latest advancements in advanced oxidation processes (AOPs), particularly the UV/chlorine combined oxidation technology. Antidepressants degrade poorly in natural aquatic environments. Removal is often incomplete and depends on processes such as adsorption, biodegradation, or photodegradation. Conventional water treatment technologies, including activated sludge systems and ozonation, demonstrate limited efficacy in removing antidepressants and may even lead to the formation of toxic by-products. In contrast, advanced oxidation processes, which generate highly reactive hydroxyl radicals (·OH) and chlorine radicals (·Cl), have proven much more effective at degrading these contaminants. Among the various AOPs, the UV/chlorine process has gained significant attention for its ability to achieve high degradation efficiency at a reasonable cost. Studies have shown that the UV/chlorine process can effectively remove over 95% of commonly found antidepressants in water, significantly reducing the risk of forming toxic by-products. However, while the UV/chlorine process displays promising results, further research is needed to enhance its adaptability to complex water matrices. The presence of other contaminants or varying water quality conditions may impact the treatment performance. This review details the reaction mechanisms, free radical generation pathways, and key influencing factors involved in the UV/chlorine process. It also identifies technical challenges, such as optimizing reaction conditions, improving process efficiency, and minimizing the harmful by-product formation. Several strategies are proposed to overcome these limitations, including adjusting operational parameters, combining the UV/chlorine process with biological treatment methods, and exploring practical applications in real-world water treatment scenarios. These insights provide a comprehensive understanding of the current state of research on the removal of antidepressants from water, offering a scientific foundation for improving drinking water treatment technologies and controlling emerging contaminants in aquatic environments. Close-