Cerium-modified iron oxides applied as catalysts in the heterogeneous Fenton system for degradation of cephalexin

Author(s)

de Lima, Amanda Santos ^[1] ; Pupo Nogueira, Raquel Fernandes ^{[1, 2]}

Affiliation

^[1] Sao Paulo State Univ UNESP, Inst Chem, BR-14800060 Araraquara, SP - Brazil

^[2] UNESP, Inst Chem, Natl Inst Alternat Technol Detect Toxicol Evaluat, BR-14800900 Araraquara, SP - Brazil

• Document type: Journal article
• Source: Environmental Science and Pollution Research; v. 28, n. 19, SI, p. 23767-23777, MAY 2021.
• Web of Science Citations: 0

Abstract

The effect of incorporation of different amounts of cerium on iron oxides and different heat treatment temperatures was evaluated for the degradation of cephalexin (CEX) using heterogeneous Fenton and photo-Fenton processes. The materials were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), specific area (BET), and zeta potential (ZP). The conversion of magnetite to maghemite was observed when a 140 degrees C thermal treatment was applied. The insertion of cerium resulted in a loss of the uniform spherical shape of the particles. The material containing the lowest amount of cerium (0.5% w/w) presented an increase in the specific area from 91.2 to 171.6 m(2) g(-1) relative to the pure iron oxide, while with 2% (w/w) a decrease to 99.2 m(2) g(-1) was observed for the materials treated at 70 degrees C. The same behavior was observed for materials treated at 140 degrees C, however, with smaller areas. At pH 6.0, a low catalytic activity was observed contrasting to the high consumption of H2O2, suggesting its catalytic decomposition into water and oxygen. This was confirmed by the very low production of HO center dot in the degradation system. On the other hand, the high production of HO center dot was observed at pH 3.5, which was chosen as a working pH. The material treated at 140 degrees C and containing 1% Ce (w/w) was the highlight, promoting degradation of 0.052 mg of CEX per m(2) area of the catalyst after 150 min using 1.0 mmol L-1 of H2O2. The CEX intermediates identified indicated hydroxylation as the major route of degradation. (AU)

• FAPESP's process: 18/12780-4 - Innovative decentralized and low cost treatment systems for optimal urban wastewater management
• Grantee: Raquel Fernandes Pupo Nogueira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/50945-4 - INCT 2014: National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactivies
• Grantee: Maria Valnice Boldrin
• Support Opportunities: Research Projects - Thematic Grants