In this work, the photoelectro-Fenton system was evaluated as an alternative for the degradation of sulfamethoxazole and trimethoprim at unmodi ed pH by using citric acid present in extracts from a natural source as organic residues (orange and lemon peels). The addition of natural citric acid showed an e cient degradation of the antibiotics similarly to the e ciency by adding commercial reagent citric acid. The observed high e ciencies and rate constants are attributed to the increment of ferrous ion in the solution due to the fast conversion of iron form its ferric to ferrous state leading to the Fenton reaction and so increasing the hydroxyl radicals production. Although the addition of citric acid present in the extracts slightly increases the organic matter of the solutions, the degradation of the antibiotics was achieved simultaneously and e ciently, converting the photoelectro-Fenton process with the addition of natural citric acid into an alternative ecological system and sustainable for water contaminated with pharmaceutics. Additionally, the high biodegradable character and low ecotoxicity of the treated solutions were determined by a modi ed Zahn Wellens test and a bioassay with D. magna, respectively. Finally, simultaneous degradation of sulfamethoxazole and trimethoprim was reached after only 45 min of treatment in which the antibacterial activity was completely eliminated, suggesting that degradation products do not represent any environmental risk nor human health.
HighlightsSMX and TMP were simultaneously degraded with the PEF process by citric acid addition. E ciency in the degradation was maintained with lemon and orange peels extract.Complete degradation of SMX and TMP increased the biodegradability of the treated solutions.The treated SMX-TMP solutions showed lower ecotoxicity.