Efficient Removal of Azo Dye from Wastewater Using the Non-Toxic Potassium Ferrate Oxidation–Coagulation Process

Abstract

The wastewater effluents from textile industries contain highly toxic metal complex dyes. For instance, azo dye has received significant attention owing to its toxicity and environmental stability. This study investigated the oxidation and coagulation processes to effectively remove azo dye from wastewater effluents. Potassium ferrate (K2FeO4) was selected as an oxidant because it has a high oxidation potential, is environmentally stable, and does not generate toxic byproducts. Moreover, it has a combination effect of coagulation and oxidation. Its performance was compared with a single oxidation process (using NaOCl) and a single coagulation process (using FeCl3·6H2O). Based on the jar test experiment, the optimized pH was estimated to be 3 and the optimal dosage was 56.4 mg/L for K2FeO4, and it removed nearly 100% of orange II azo dye (OD) and lissamine green B dye (LGB). However, its removal efficiency decreased when the pH increased to 12. In all processes, dye removal was completed in 5 min of the reaction. Overall, OD and LGB were effectively removed by K2FeO4, compared to the NaOCl and FeCl3·6H2O. This indicates that the combination of oxidation and coagulation of K2FeO4 outperformed the single treatment process without toxic byproduct production.

Synthesis of Nano‐zero‐valent Iron/Chitosan based on Bimetallic Nanoparticles for the Simultaneous Removal of Reactive Violet 5 and Reactive Blue 171 from Aquatic Media: Response Surface Methodology

“…The removal of RV5 and RB171 was assessed by nZVI-CS-Cu and the removal percentage was achieved at diverse experimental parameters. These conditions include pH of 3 to 9, contact time of 5 to 15 min, initial concentration of 5 to 40 mg L À 1 , and adsorbent dosage of 0.1 to 0.3 g. Three replications were considered for the experiments and the dye removal percentage was calculated using Eq (12).…”

“…[10] Due to environmental, toxicological, and chemical problems, finding the most suitable method for the treatment of industrial effluents has been considered by researchers. [11] There are currently various treatment techniques, including oxidation-coagulation, [12] advanced oxidation, [13] photo-assist advanced oxidation process, [14] coagulation, [15,16] ozonation, [17] reverse osmosis and nanofiltration, [18] nanofiltration, [19] electrochemical, [20,21] photo-Fenton [22] and adsorption [23] for the removal of dyes. Among them, adsorption has been widely accepted for the elimination of pollutants from aqueous media due to its simple process, inexpensive, and efficient nature.…”

Degradation of Anthraquinone Dye Wastewater by Sodium Percarbonate with CoO Heterogeneous Activation

“…Such a complex structure makes anthraquinone dyes not only able to exist stably in water environment, but also more toxic than azo dyes. However, due to its simple synthesis process, low cost, excellent dyeing performance, it has found widespread application in the textile [3,4], paper [5], food [6] and leather [7] industries. Ahmed Malik et al used bioreactors to treat textile dye wastewater from denim textile mills to increase the MLSS concentration removal rate increased by 13.9%, but the high energy consumption and the large amount of treated sludge are not applicable to the degradation of high-concentration wastewater [8].…”

The Effect of Modifying Canadian Goldenrod (Solidago canadensis) Biomass with Ammonia and Epichlorohydrin on the Sorption Efficiency of Anionic Dyes from Water Solutions

“…Decolorization of wastewater via dye oxidation is quick and easy to carry out, but does not prove effective enough for all groups of dyes. In addition, in systems based on chemical oxidation, there is a high risk of accumulation of intermediate oxidation products (e.g., aromatic amines), which are much more toxic than dyes [ 9 ]. Systems based on reverse osmosis ensure the highest efficiency of colored wastewater treatment [ 10 ]; however, they require expensive membranes and high pressures of up to 2.5 MPa to operate.…”