Degradation of Azo-dye Orange II by a Photoassisted Fenton Reaction Using a Novel Composite of Iron Oxide and Silicate Nanoparticles as a Catalyst

Abstract

A novel nanocomposite of iron oxide and silicate, prepared through a reaction between a solution of iron salt and a dispersion of Laponite clay, was used as a catalyst for the photoassisted Fenton degradation of azo-dye Orange II. This catalyst is much cheaper than the Nafion-based catalysts, and our results illustrate that it can significantly accelerate the degradation of Orange II under the irradiation of UV light (λ = 254 nm). An advantage of the catalyst is its long-term stability that was confirmed through using the catalyst for multiple runs in the degradation of Orange II. The effects of the H2O2 molar concentration, solution pH, wavelength and power of the UV light, catalyst loading, and initial Orange II concentration on the degradation of Orange II were studied in detail. In addition, it was also found that discoloration of Orange II undergoes a faster kinetics than mineralization of Orange II and 75% total organic carbons of 0.1 mM Orange II can be eliminated after 90 min in the presence of 1.0 g of Fe-nanocomposite/L, 4.8 mM H2O2, and 1 × 8W UVC.

Mineralization of an azo dye Acid Red 14 by photoelectro-Fenton process using an activated carbon fiber cathode

“…The change in the solution pH is related to the acidity of the intermediates produced during the degradation of AR14. A similar phenomenon was reported by Feng et al [42] and Dhananjeyan et al [43] in photoassisted Fenton degradation of azo dye Orange II mediated by heterogeneous Fenton reaction. They attributed the drop in the solution pH to two main factors.…”

Adsorption and photodegradation of Procion yellow H-EXL dye in textile wastewater over TiO2 suspension

“…Among these treatments, advanced oxidation processes (AOPs) are powerful alternative to conventional treatment methods for such wastewater decontamination (Andreozzi et al 1999;Munter et al 2001;Tarr et al 2003;Parsons et al 2004). Most of those works were focused on treatment with Fenton, photo-Fenton (UV/Fenton) or photoFenton-like reactions (Kang et al 2000;Feng et al 2003;Neyens et al 2003;Swaminathan et al 2003;Lucas et al 2006;Sanja et al 2008), UV + H 2 O 2 (or O 3 ) (Arslan et al 1999;Karadimas et al 2003;Arslan et al 2002), photocatalysis (UV + TiO 2 or other semiconductor particles) (Arslan et al 2000;Tanaka et al 2000;Poulios et al 2003;Rao et al 2003;Danfeng et al 2004;Dong et al 2007;Wu et al 2008). These treatments are based on the in situ generation of highly reactive hydroxyl radicals (HO•).…”

Degradation of dyes in aqueous solutions by the Fenton process

“…However, sludge generation and adsorbent regeneration are the principal weakness of these processes (Slokar and Majcen Le Marechal, 1998). The Fenton process that uses Fe 2+ to react with H 2 O 2 to generate OH with powerful oxidizing ability, one of the advanced oxidation processes (AOPs), has been proposed for the degradation of organic pollutants (Chen and Pignatello, 1997;Benitez et al, 2001;Huang et al, 2002), including some dye pollutants (Kang et al, 2002;Feng et al, 2003;Swaminathan et al, 2003).…”