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Research article2020Peer reviewedOpen access

Simultaneous degradation of 30 pharmaceuticals by anodic oxidation: Main intermediaries and by-products

Calzadilla, Wendy; Carolina Espinoza, L.; Silvia Diaz-Cruz, M.; Sunyer, Adria; Aranda, Mario; Pena-Farfal, Carlos; Salazar, Ricardo


The anodic oxidation (AO) of 30 pharmaceuticals including antibiotics, hormones, antihistaminics, anti-inflammatories, antidepressants, antihypertensives, and antiulcer agents, in solutions containing different supporting electrolytes media (0.05 M Na2SO4, 0.05 M NaCl, and 0.05 M Na2SO4 + 0.05 M NaCl) at natural pH was studied. A boron-doped diamond (BDD) electrode and a stainless-steel electrode were used as anode and cathode, respectively, and three current densities of 6, 20, and 40 mA cm(-2) were applied. The results showed high mineralization rates, above 85%, in all the tested electrolytic media. 25 intermediaries produced during the electrooxidation were identified, depending on the supporting electrolyte together with the formation of carboxylic acids, NO3-, SO42- and NH4+ ions. The formation of intermediates in chloride medium produced an increase in absorbance. Finally, a real secondary effluent spiked with the 30 pharmaceuticals was treated by AO applying 6 mA cm(-2) at natural pH and without addition of supporting electrolyte, reaching c.a. 90% mineralization after 300 min, with an energy consumption of 18.95 kW h m(-3) equivalent to 2.90 USD m(-3). A degradation scheme for the mixture of emerging contaminants in both electrolytic media is proposed. Thus, the application of anodic oxidation generates a high concentration of hydroxyl radicals that favors the mineralization of the pharmaceuticals present in the spiked secondary effluent sample. (C) 2020 Elsevier Ltd. All rights reserved.


Anodic oxidation; Boron-doped diamond electrode; Hydroxyl radical; Pharmaceuticals; Secondary effluent

Published in

2020, Volume: 269, article number: 128753

    UKÄ Subject classification

    Environmental Sciences

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