Degradation of azo dye with activated peroxygens: when zero-valent iron meets chloride

Abstract

Selection of the most appropriate Fe-based peroxygen oxidation technology depends on the dye wastewater constituents and pH.

RETRACTED: Fe3O4 Nanoparticles Grown on Cellulose/GO Hydrogels as Advanced Catalytic Materials for the Heterogeneous Fenton-like Reaction

“…18−21 Therefore, the Fenton or Fenton-like reactions generally occur at the solid–liquid interfaces, where the iron remains substantially in the solid phase either as a mineral or as an adsorbed ion. 18,22 In particular, carbonaceous materials, such as activated carbon (AC), 20,23,24 carbon nanotubes (CNTs), 18,21,25 mesoporous carbon, 26 and carbon aerogels, 20,27 have been well proven as catalyst carriers to immobilize the iron species because of their special performance as a cocatalyst. Recently, Voitko et al 28 reported that graphene oxide (GO) showed better degradation performance than CNTs and AC, which was attributed to the many oxygen-containing functional groups of the GO plates.…”

An efficient strategy for full mineralization of an azo dye in wastewater: a synergistic combination of solar thermo- and electrochemistry plus photocatalysis

“…10, the oxidation efficiency is 54.35%, 67.25%, 76.95%, and 81.88% at of 20 C, 40 C, 60 C, and 80 C, respectively. The oxidation process of methyl orange indicates that molecular conjugate chains are gradually shortened, 41,42 which can be reected in the UV spectrum. The oxidation of methyl orange typically involves the cleavage of the azo bond, the breakdown of the benzene ring, and the formation of small inorganic molecules; these steps are described as decolorization, degradation, and mineralization in this study.…”

Electrochemical Degradation of Industrial Dyes in Wastewater through the Dissolution of Aluminum Sacrificial Anode of Cu/Al Macro-Corrosion Galvanic Cell

“…It is well-known [ 46 , 47 , 48 ] that the oxidation process of the azo dyes typically begins with a break of the azo bond (a decolourization stage). It is then followed by the degradation of benzene ring in the dye molecule to finally undergo complete or partial mineralization process.…”

“…It is then followed by the degradation of benzene ring in the dye molecule to finally undergo complete or partial mineralization process. These effects could be visualized by absorbance changes within the UV-VIS spectrum for the selected wavelength ranges, namely: 350–600, 265–350 and 200–265 nm, correspondingly [ 46 , 47 , 48 , 49 , 50 , 51 ].…”

“…During the decolourization stage, the azo bond (–N=N–), which is a chromogenic group, becomes an acceptor for electrons released during the anodic oxidation process. Thus, the dye molecule breaks down into aromatic/phenol and aromatic amine derivatives, which are structurally similar to 3-Amino-2-hydroxy-5-nitrobenzenesulfonic acid or 2-chloro-4-nitrobenzenamine [ 46 , 47 , 48 ]. The increase in the absorbance recorded for the Disperse Red 167 during the first 900 s of the experiment was most likely connected with partial multimerization of the electrolysis products or else with the process of electrochemical coagulation [ 52 , 53 , 54 , 55 ].…”