Photochemical persistence of sulfa drugs in aqueous medium: kinetic study and mathematical simulations
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ADVANCED OXIDATION/REDUCTION TECHNOLOGIES: AN PERSPECTIVE FROM IBEROAMERICAN COUNTRIES
Photochemical persistence of sulfa drugs in aqueous medium: kinetic study and mathematical simulations Arlen Mabel Lastre-Acosta 1,2 & Bruno Segawa Cristofoli 1 & Marcela Prado Silva Parizi 3 & Claudio Augusto Oller do Nascimento 2 & Antonio Carlos Silva Costa Teixeira 1 Received: 17 July 2020 / Accepted: 16 November 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract This study aimed at investigating the photochemical behavior of sulfa drugs containing five and six-membered heterocyclic substituents (sulfamethoxazole (SMX) and sulfadiazine (SDZ), respectively), in an aqueous medium. Despite their importance, studies devoted to the use of photochemical models to predict the environmental phototransformation of pollutants in surface waters, by combining laboratory results and natural aquatic systems parameters, are still scarce in the scientific literature. In this work, the second-order reaction rate constants of SDZ and SMX with hydroxyl radicals (●OH), singlet oxygen (1O2), and triplet excited states of chromophoric dissolved organic matter (3CDOM*) were experimentally determined at pH 7, using the competition kinetics approach. The results show that ●OH and 3CDOM* are the key species involved in sulfonamide degradation, with anionic SMX, most prevalent at pH 6–9, being degraded much slower than the anionic form of SDZ. Moreover, SDZ and SMX photodegradation in natural water samples (spring-fed natural pond, public supply reservoir, and sea water) was significantly enhanced relative to depletion in pure water. Finally, from mathematical simulations of the sunlight-driven sulfonamide degradation, half-life times were predicted for these drugs varying from less than 2 to about 90 days, depending on the water depth, concentration of key species (DOC, HCO3−, NO2−, CO32−) in natural aqueous systems, as well as on the particular heterocyclic substituent. Keywords Sulfonamides . Environmental persistence . Reactive photo-induced species (RPS) . Photolysis . Real aqueous matrices . Mathematical modeling
Introduction Sulfonamide antibiotics are widely used in aquaculture, for veterinary purposes in the treatment and prevention of Responsible Editor: Vítor Pais Vilar * Arlen Mabel Lastre-Acosta [email protected] 1
Research Group in Advanced Oxidation Processes (AdOx), Department of Chemical Engineering, University of São Paulo, Av. Prof. Luciano Gualberto, tr. 3, 380, São Paulo, SP, Brazil
2
Chemical Systems Engineering Center, Department of Chemical Engineering, University of São Paulo, Av. Prof. Luciano Gualberto, tr. 3, 380, São Paulo, SP, Brazil
3
Energy Engineering Department, São Paulo State University (UNESP), Av. Dos Barrageiros, 1881, Rosana, SP, Brazil
infectious diseases caused by bacteria, and for treating respiratory and urinary tract infections in humans (Boreen et al. 2004). Members of this class of pharmaceuticals contain an identical backbone structure, only differing in the N-bound su
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