Decolorization and mineralization of Sunset Yellow FCF azo dye by anodic oxidation, electro-Fenton, UVA photoelectro-Fenton and solar photoelectro-Fenton processes

• Type: Article in International Scientific Journal
• Date: 2013

Authors

Francisca C. Moreira (Author) FEUP; Sergi Garcia-Segura (Author) Other; Vítor J. P. Vilar (Author) FEUP; Rui A. R. Boaventura (Author) FEUP; Enric Brillas (Author) Other

Journal

Title: Applied Catalysis B: Environmental

Vol. 142 No. OCT-NOV 2013

Pages: 877-890

ISSN: 0926-3373

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 105 Citations

ISI Web of Science

Scopus - 146 Citations

Scientific classification

FOS: Engineering and technology

CORDIS: Technological sciences

Associated Projects

LA 20 - Projeto Estratégico-LA 20 - 2011-2012

Other information

Authenticus ID: P-006-732

DOI: 10.1016/j.apcatb.2013.03.023

Abstract (EN): The decolorization and mineralization of 100 mL of 290 mg L-1 Sunset Yellow FCF (SY) azo dye at pH 3.0 were studied by anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar photoelectro-Fenton (SPEF). Trials were performed in a one-compartment cell equipped with a boron-doped diamond (BDD) anode and a carbon-PTFE air-diffusion cathode. Organics were removed by hydroxyl radical ((OH)-O-center dot) formed: (i) at the BDD anode from water oxidation, (ii) in the bulk from Fenton's reaction between added Fe2+ and generated H2O2 at the cathode and (iii) from the photolysis of Fe(OH)(2+) species by UV light. The most powerful method was SPEF, achieving an almost total mineralization more rapidly than PEF due to the higher UV intensity of sunlight, which quickly photolyzes Fe(III)-carboxylate complexes that cannot be destroyed by (OH)-O-center dot in EF. However, SY was completely decolorized at similar rate by EF, PEF and SPEF. The little oxidation action of (OH)-O-center dot at the BDD anode yielded a slow decolorization and mineralization in AO-H2O2. The effect of current density on all treatments was examined. The azo dye decay always followed a pseudo-first-order reaction. It was more rapidly removed than decolorized, indicating that colored aromatic products are involved in the decolorization process. A total of 14 aromatic products and 34 hydroxylated derivatives, including benzenic, naphthalenic and phthalic acid compounds, were detected by LC-MS. Generated carboxylic acids like tartronic, oxalic, formic and oxamic were identified by ion-exclusion HPLC. The viability of SPEF at industrial scale was demonstrated using a solar pre-pilot plant with a Pt/carbon-PTFE air-diffusion cell coupled with a compound parabolic collectors (CPCs) photoreactor. In this plant, the treatment of 101 of 290 mg L-1 SY at pH 3.0 between 33.2 and 77.6 mA cm(-2) gave total decolorization and 91-94% mineralization in short time. A plausible general reaction sequence for SY mineralization involving all oxidation products detected was proposed.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 14