Industrialization has led to a severe deterioration in water quality. Textile industry is considered a huge consumer of water in Egypt; the result is generating large amounts of dye-containing wastewater that is essential to be treated before the final disposal. However, searching for efficient treatment is an important aspect for a sustainable environment. Advanced oxidation processes (AOPs) have been emerged as efficient techniques for industrial wastewater remediation. Among the AOPs, Fenton based reactions is considered a promising process for its simplicity in application and cost-efficient with high process efficiency. In this study, heterogeneous Fenton reaction using magnetite nanoparticles induced by ultraviolet radiation (UV) was applied as a green technology pathway for textile dyeing wastewater oxidation. Nanostructured magnetite was successfully obtained by co-precipitation technique that is used as the precursor of the Fenton’s reaction process. The heterogeneous iron (Fe2+/Fe3+) supported catalyst with hydrogen peroxide (H2O2) was used as a coupled Fenton and Fenton-like oxidation system for methylene blue dye removal in aqueous media. The obtained results investigated that the dye oxidation rate increases with decreasing pH to 3.0. However, increasing H2O2 and magnetite (Fe3O4) nanoparticles catalyst results in an increase in the dye oxidation rate and the optimum operating values were 80 and 1600 mg/L for Fe3O4 and H2O2, respectively. By optimizing the amount of reagents, process conditions as well, the results revealed that magnetite was considered an efficient Fenton-based catalyst for dye oxidation that is reached to 94% within 3 hr of oxidation time. Finally, magnetite catalyst could be easily recovered by magnetic separation to confirm the process sustainability.

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Alum sludge (AS) is produced in inevitable amounts from drinking water treatment plants. Also, dye-contaminating wastewater is usually discharged from textile industries that must be treated to meet the environmental authorities; thus, Fenton’s reagent is a suitable candidate. However, reducing the quantity of chemicals used in Fenton reactions can be partly achieved by an industrial ecology approach. This paper is introducing alum sludge waste as a photocatalyst, (termed as AS-Fenton), that is prepared under mild experimental conditions. Thermogravimetric and differential thermogravimetric analyses were conducted to attain full illustrations of the thermal treatment steps. Its chemical composition and morphology is revealed using X-Ray Diffraction and Scanning Electron Microscope. Thus, this research is of great significance for the application of a waste by-product for being a Fenton source for photocatalytic removal of Levafix Blue dye effluent. A new modified Fenton reagent was applied with the addition of 1.0 g/L and 800 mg/L of catalyst and H2O2, respectively, at pH 3.0 shows high potential for the dye removal. The starting concentration of the Levafix Blue CA was halved during the first 5 min under the UV illumination. The most effective operating variables are optimized through Response Surface Methodology. The kinetics of the dye removal was investigated and the reaction following the pseudo-first-order regime with the kinetic constant (KF), ranged in 0.04–0.57 min−1. Thermodynamic parameters reveal that the reaction is a non-spontaneous and endothermic in nature. Hence, toxicity of the dye is significantly reduced via Fenton reaction to non-toxic end products.

Dyes represent major environmental concerns since their presence in aqueous effluents posed a threat to the ecological system. This work is focused on developing a sustainable photo-Fenton strategy for efficient Levafix Blue oxidation. Nanostructured magnetite as the precursor of the oxidation technique has been synthesized via a simple co-precipitation technique. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were applied to characterize the samples.The experimental dye removal data revealed that almost complete dye removal (99.9%) was attained at pH 3.0 using 800 and 40 mg/L of H 2 O 2 and magnetite reagents, respectively within 30-min of irradiation time. The process follows the first-order reaction model with endothermic and non-spontaneous oxidation reaction in nature with a low activation energy barrier of 14.29 kJ/mol. Finally, the experimental data reveals that magnetite could be easily recovered and recycled up to six treatment cycles with a removal efficiency of 71% confirms the process sustainability.

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