Residue-based iron oxide catalyst for the degradation of simulated petrochemical wastewater via heterogeneous photo-Fenton process

ABSTRACT

Iron oxide with a high degree of purity was recovered from waste and used as an environmentally friendly, low-cost catalyst in the application of the photo-Fenton process to simulated petrochemical wastewater (SPW). Iron oxide nanoparticles were characterized by X-ray powder diffraction, transmission electron microscopy, N₂ adsorption/desorption isotherms, zeta potential, toxicity and atomic absorption spectrometry. The experiments were performed in a batch photochemical reactor, at 20 ± 2.0°C and pH 3.0. The SPW was efficiently mineralized and oxidized using a low catalyst dosage. The results showed that the organic compounds present in the wastewater were not adsorbed onto the solid surface. The solid was found to be stable with negligible leaching and low toxicity. The k_TOC/k_COD ratios were calculated and varied according to the process: for a homogeneous reaction, the ratio obtained was 0.31 and for the heterogenous photo-Fenton process, it was closer to 1. The chemical oxygen demand and total organic carbon removal values were very close, indicating that the SPW is immediately mineralized, without producing partially oxidized compounds. The residue-based goethite studied represents a good alternative to commercially available catalysts in terms of sources and availability.

KEYWORDS:

• Residue based iron-oxide
• advanced oxidation process
• photo-Fenton
• phenolic compounds
• petrochemical wastewater

Acknowledgments

The authors would like to acknowledge the Brazilian governmental agencies CAPES – Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil and CNPq – Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil, for their financial support and Laboratório Central de Microscopia Eletrônico (LCME/UFSC) for the TEM analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Regina De Fátima Peralta Muniz Moreira http://orcid.org/0000-0002-2863-7260

Additional information

Funding

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico [grant number 405892/2013 6] and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior for scholarships.