The Direct Formation of an Iron Citrate Complex Using a Metallurgical Slag as an Iron Source for Micropollutant Removal via the Photo-Fenton Process
Por:
Arzate Salgado S.Y., Yañez-Aulestia A., Ramírez-Zamora R.-M.
Publicada:
1 ene 2024
Resumen:
Following the goals of the circular economy, this work demonstrates that an industrial by-product can be used in environmental remediation. Metallurgical slag and citric acid were used to form an Fe:Cit complex by simultaneously carrying out the lixiviation of the iron and the chelating stages with an 87% iron recovery. This complex was evaluated in the photo-Fenton process to produce HO• through salicylic acid dosimetry or salicylic acid hydroxylation, producing 0.13 ± 0.1 mM HO• after 30 min of operation; such a value is three orders of magnitude higher than the one reported for the metallurgical slag (as a heterogeneous catalyst, 22 µM) in the photo-Fenton-like process. The system was tested for its ability to degrade a mixture of drugs, including dexamethasone (DEX), naproxen (NAP), and ketorolac (KTR), which are often used to treat the symptoms of COVID-19. The drug degradation tests were performed in two stages. In the first stage, the Fe:Cit complex from the metallurgical slag was compared to the one formed by analytical-grade reactants; the drug degradation was faster for the former, with the major difference being observed at 5 cm and 500 W/m2. Here, 85–90% of the drugs was degraded in 5 min using Fe:Cit from slag, while at least 20 min was necessary to achieve such degradation with the analytical reagent, conceivably because of the trace compounds being lixiviated from the slag. Then, the effects of the liquid depth (5, 10, and 15 cm) and irradiance (250, 500, and 750 W/m2) were tested; the pseudo-first-order kinetic degradation constants for the three model pollutants were in the range of 0.009 > kD > 0.09 min-1, showing that degradation is more feasible for DEX than for NAP and KRT because the radical attack feasibility is related to the molecular structures. © 2024 by the authors.
Filiaciones:
Arzate Salgado S.Y.:
Coordinación de Ingeniería Ambiental, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Circuito Escolar s/n, Ciudad Universitaria, Coyoacán, Ciudad de Mexico, 04510, Mexico
Yañez-Aulestia A.:
Coordinación de Ingeniería Ambiental, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Circuito Escolar s/n, Ciudad Universitaria, Coyoacán, Ciudad de Mexico, 04510, Mexico
Ramírez-Zamora R.-M.:
Coordinación de Ingeniería Ambiental, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Circuito Escolar s/n, Ciudad Universitaria, Coyoacán, Ciudad de Mexico, 04510, Mexico
gold, All Open Access; Gold Open Access
|