From Tetracycline to Sulfamethoxazole: Photocatalytic Degradation and Mechanistic Insights in Aquatic Environments

ABSTRACT

The pollution caused by antibiotics to aquatic ecosystems is becoming increasingly serious, thus more effective treatment methods are urgently required. Although the photocatalytic degradation behavior of tetracycline (TC) is relatively well understood, sulfamethoxazole (SMZ), an emerging pollutant originating from large‐scale livestock operations, is considerably more difficult to treat, owing to its elevated aqueous solubility and inherent stability against photodegradation. This review first reveals that SMZ undergoes slower photocatalytic degradation than TC, and further elucidates the fundamental mechanistic distinctions underlying their degradation pathways. Additionally, a systematic comparison of catalyst design strategies reported over the last 5 years is presented, highlighting how even minor variations in catalyst architecture can profoundly influence reactive oxygen species (ROS) production and interfacial electron transfer. Importantly, it is demonstrated that the removal of contaminants does not necessarily guarantee enhanced water safety. However, achieving genuine detoxification extends beyond mere contaminant degradation, as evidenced by ecotoxicity assessments conducted on antibiotic transformation products. Finally, a shift from the traditional “broad‐spectrum removal” paradigm toward “precise molecular catalysis” is proposed, along with the development of catalytic systems tailored for the complex antibiotic mixtures encountered in real aquatic environments.