Degradation of Organic Methyl Orange (MO) Dye Using a Photocatalyzed Non-Ferrous Fenton Reaction

Abstract

Removal of recalcitrant organic pollutants by degradation or mineralization from industrial waste streams is continuously being explored to find viable options to apply on the commercial scale. Herein, we propose a titanium nanotube array (based on a non-ferrous Fenton system) for the successful degradation of a model contaminant azo dye, methyl orange, under simulated solar illumination. Titanium nanotube arrays were synthesized by anodizing a titanium film in an electrolyte medium containing water and ethylene glycol. Characterization by SEM, XRD, and profilometry confirmed uniformly distributed tubular arrays with 100 nm width and 400 nm length. The non-ferrous Fenton performance of the titanium nanotube array in a minimal concentration of H2O2 showed remarkable degradation kinetics, with a 99.7% reduction in methyl orange dye concentration after a 60 min reaction time when illuminated with simulated solar light (100 mW cm−2, AM 1.5G). The pseudo-first-order rate constant was 0.407 µmol−1 min−1, adhering to the Langmuir–Hinshelwood model. Reaction product analyses by TOC and LC/MS/MS confirmed that the methyl orange was partially fragmented, while the rest was mineralized. The facile withdrawal and regeneration observed in the film-based titanium nanotube array photocatalyst highlight its potential to treat real industrial wastewater streams with a <5% performance drop over 20 reaction cycles.

Preparation of Oxygen-Doping Nongraphitic Carbon Nitride via Efficiency Exfoliation for the Application of Photocatalytic Degradation

“…The degradation products were characterized by electrospray quadrupole mass spectrometry (ESI Q MS), and the structural information on the possible intermediates in the degradation process have been listed in Table S3, and the mass spectra of some substances were shown in Figures S10–S15. The possible degradation pathway was speculated in conjunction with the literature, − as shown in Figure . The mass spectral signal of MO corresponded to the deprotonated ion [M – H] − at m / z = 304, and all products were deprotonated ions [M – H] − obtained by ionization in the mass spectrum.…”

Surface Adsorption and Photoinduced Degradation: A Study of Spinel Ferrite Nanomaterials for Removal of a Model Organic Pollutant from Water

“…Previous studies of methyl orange degradation employing total organic carbon (TOC) analysis demonstrate that decolorization is associated with loss of organic carbon, indicating the formation of inorganic products, which would be consistent with mineralization. 60,61 One recent study of methyl orange photodegradation by surface-modified Fe 3 O 4 nanoparticles in the presence of H 2 O 2 demonstrated that the colorless degradation products are significantly less toxic to fish than methyl orange. 62 Given the similarity of this photodegradation approach with the spinel ferrite photodegradation systems that are the subject of this Perspective, we strongly suspect that the colorless degradation products produced here are also primarily nontoxic mineralization products.…”