Ferrioxalate complexes as strategy to drive a photo-FENTON reaction at mild pH conditions: A case study on levofloxacin oxidation

• Type: Article in International Scientific Journal
• Date: 2017-05-17

Authors

Vítor J. P. Vilar (Author) FEUP; André A. Nogueira (Author) Other; Bianca M. Souza (Author) Other; Márcia W. C. Dezotti (Author) Other; Rui A. R. Boaventura (Author) FEUP

Journal

Title: Journal of Photochemistry and Photobiology A: Chemistry

Vol. 345

Pages: 109-123

ISSN: 1010-6030

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 18 Citations

ISI Web of Science

Scopus - 39 Citations

Scientific classification

CORDIS: Technological sciences > Technology > Environmental technology

FOS: Engineering and technology > Environmental engineering

Associated Projects

LSRE-LCM - Laboratório de Processos de Separação e Reação - Laboratório de Catálise e Materiais

Other information

Authenticus ID: P-00M-VV5

DOI: 10.1016/j.jphotochem.2017.05.020

Abstract (EN): The present study is about the use of ferrioxalate photoactive complexes as a strategy to drive a photo Fenton reaction at mild pH conditions, applied to the oxidation of antibiotic levofloxacin (LEV) in pure water and spiked in urban wastewater after secondary treatment. The oxidation ability of the solar photo Fenton mediated by ferrioxalate complexes (SPFF) was evaluated at different pH values (3.0 to 6.0) for an iron/oxalate molar ratio of 1:3 and using low iron contents (1.0 and 2.0 mg Fe3+ L-1). Additionally, the effect of LEV concentration (2-20 mg L-1), iron:oxalate molar ratio (1:3, 1:6 and 1:9), temperature (1545 degrees C), UVA irradiance (27.8-59.9 Wuv m(-2)), presence of inorganic ions (Cl-, SO42-, HCO3-, NH4+), radical scavengers (sodium azide, humic acid and D-mannitol), and others organic ligands, namely citrate and malate, on the SPFF method at pH 5.0 was also assessed. Although the conventional solar photo-Fenton (CSPF) reaction showed similar results to SPFF for pH values <= 4, an almost 3.3-fold and 5.7-fold increase in the LEV degradation rate at pH 5.0 and 6.0, respectively, were observed for SPFF when compared to CSPF. This is mainly attributed to the higher photoactivity and solubility of ferrioxalate complexes when compared with ferric ion-water complexes. On the other hand, ferrioxalate complexes exhibited higher photoactivity on LEV removal than ferricitrate and ferrimalate. The presence of phosphate ions in the urban wastewater affected negatively the reaction rate, mainly due to the precipitation of iron as FePO4(s), hence a H2O2/UVC process at different conditions was also explored as an alternative. A pilot-scale assay under natural solar irradiation showed similar results to the ones obtained in the lab-scale photoreactor. Oxalic, formic, citric, and tartronic acids were identified as residual acids in SPFF at pilot scale.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 15