Mechanistic insight into the aqueous transformation of sartans by ozonation and the Fe(II)/peroxymonosulfate system

With the aging of the global population and continued economic development, the use of sartan-type antihypertensive drugs (e.g., losartan (LOS), telmisartan (TEL), and valsartan (VAL)) has increased with widespread contamination issues. However, the effect of advanced oxidation processes (AOPs) on the degradation of sartans remains unknown. Therefore, AOPs such as the Fe(II)/peroxymonosulfate (PMS) system and ozonation were used to treat the typical sartans, which led to the formation of various transformation products (TPs). This research involves the formation mechanisms of these TPs following AOPs including aldolization, hydroxylation, ring cleavage, carbonylation and cyclization. The risk evaluation focused on the biodegradability and toxicity of the drugs and their TPs, assessed using computerized toxicity prediction software. The findings indicated that the biodegradability of most TPs was generally poor and most TPs exhibited acute/chronic toxicity. This underscores the need for caution when applying AOPs in water treatment to prevent secondary contamination and suggests the potential necessity of integrating AOPs with complementary purification technologies. This research provides novel insights into the degradation pathways and environmental risks of sartans, emphasizing the importance of a holistic approach to water treatment.