Superior selectivity of high-frequency ultrasound toward chorine containing-pharmaceuticals elimination in urine: A comparative study with other oxidation processes through the elucidation of the degradation pathways

• Published in: Ultrasonics sonochemistry 2021-12, Vol.80, p.105814-105814, Article 105814
• Main Authors: Serna-Galvis, Efraím A., Guateque-Londoño, John F., Silva-Agredo, Javier, Porras, Jazmín, Ávila-Torres, Yenny, Torres-Palma, Ricardo A.
• Format: Article
• Language: English
• Subjects: Biological activity changes; Cloxacillin; Degradation routes; Diclofenac; Halogenated pharmaceuticals elimination; Hydrogen Peroxide; Hydroxyl Radical; Losartan; Original; Pharmaceutical Preparations; Processes selectivity; Sonochemical system; Ultrasonics; Urine treatment; Water Pollutants, Chemical - analysis
• ISSN: 1350-4177; 1873-2828
• DOI: 10.1016/j.ultsonch.2021.105814

•Three halogenated pharmaceuticals of different therapeutic groups were treated in urine.•Selectivity comparison for sono-treatment, UVC/H2O2and electrochemical oxidation.•Kinetics depended on chemical properties of pollutants and degradation routes of processes.•Sono-treatment showed higher selectivity for pollutants degradation in urine.•Sono-treatment decreased biological activity associated withthe pharmaceuticals. This work considered the sonochemical degradation (using a bath-type reactor, at 375 kHz and 106.3 W L-1, 250 mL of sample) of three representative halogenated pharmaceuticals (cloxacillin, diclofenac, and losartan) in urine matrices. The action route of the process was initially established. Then, the selectivity of the sonochemical system, to degrade the target pharmaceuticals in simulated fresh urine was compared with electrochemical oxidation (using a BDD anode, at 1.88 mA cm−2), and UVC/H2O2 (at 60 W of light and 500 mol L-1 of H2O2). Also, the treatment of cloxacillin in an actual urine sample by ultrasound and UVC/H2O2 was evaluated. More than 90% of the target compounds concentration, in the simulated matrix, was removed after 60 min of sonication. However, the sono-treatment of cloxacillin in the real sample was less efficient than in the synthetic urine. The ultrasonic process achieved 43% of degradation after 90 min of treatment in the actual matrix. In the sonochemical system, hydroxyl radicals in the interfacial zone were the main degrading agents. Meanwhile, in the electrochemical process, electrogenerated HOCl was responsible for the elimination of pharmaceuticals. In turn, in UVC/H2O2 both direct photolysis and hydroxyl radicals degraded the target pollutants. Interestingly, the degradation by ultrasound of the pharmaceuticals in synthetic fresh urine was very close to the observed in distilled water. Indeed, the sonodegradation had a higher selectivity than the other two processes. Despite the sono-treatment of cloxacillin was affected by the actual matrix components, this contrasts with the UVC/H2O2, which was completely inhibited in the real urine. The sonochemical process led to 100% of antimicrobial activity (AA) elimination after 75 min sonication in the synthetic urine, and ∼ 20% of AA was diminished after 90 min of treatment in the real matrix. The AA decreasing was linked to the transformations of the penicillin nucleus on cloxacillin, the region most prone to electrophilic attacks by radicals according to a density