Removal of drug losartan in environmental aquatic matrices by heat-activated persulfate: Kinetics, transformation products and synergistic effects

• Published in: Chemosphere (Oxford) 2022-01, Vol.287, p.131952-131952, Article 131952
• Main Authors: Ioannidi, Alexandra, Arvaniti, Olga S., Nika, Maria-Christina, Aalizadeh, Reza, Thomaidis, Nikolaos S., Mantzavinos, Dionissios, Frontistis, Zacharias
• Format: Article
• Language: English
• Subjects: Advanced oxidation processes; Losartan (LOS); Synergy; Thermal activation; Transformation products; Water treatment
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2021.131952

In this study, the oxidative degradation of losartan (LOS), a widely administered medicine for high blood pressure by heat-activated persulfate was investigated. Increased temperature and persulfate concentration, as well as acidic conditions enhance the degradation efficiency of LOS, whose rate follows pseudo-first order kinetics. From the respective apparent rate constants in the range 40–60 °C, an apparent activation energy of 112.70 kJ/mol was computed. Radical scavenging tests demonstrated that both HO• and SO4•− contribute towards LOS degradation. LOS degradation was suppressed in real water matrices including bottled water (BW) and secondary wastewater effluent (WW), while other experiments indicated that the presence of bicarbonates and humic acid negatively affected its oxidation. Instead, the addition of chloride ions at 250 mg/L resulted in a positive effect on LOS removal. The combination of heat-activated PS with low-frequency ultrasound exhibited a synergistic effect, with the ratio S being 2.29 in BW and 1.52 in WW. Five transformation products of LOS were identified through HRMS suspect and non-target screening approaches, among which two are reported for the first time. Using the in-house risk assessment program, ToxTrAMs was revealed that most of the identified TPs present higher toxicity than LOS against Daphnia magna. •Equally important to process performance is the complexity of the water matrix.•The detrimental effect of environmental matrices may be offset by hybrid processes.•The combined heat/us/persulfate process showed synergy in different matrices.•HRMS analysis revealed the formation of five LOS transformation products.