Adsorption and Fenton oxidation of azo dyes by magnetite nanoparticles deposited on a glass substrate

Abstract

Abstract Fenton oxidation is an efficient and useful method for wastewater treatment. To increase overall reaction efficiencies and inhibit environmental impacts, developing advanced catalysts are crucial in this matter. The main goal of this study was to investigate the catalytic activity of the magnetite (Fe2+Fe23+O42−, FeFe2O4, or Fe3O4) nanoparticles (NPs) coated borosilicate glass on the color removal of basic red 18 (BR18) and acid red 8 (AR88) azo dyes by adsorption and Fenton oxidation reaction. The efficiency of powder magnetite NPs was also tested to compare to magnetite NPs coated borosilicate glass. The effect of solution pH (2.5–9.0), catalyst loading (0.25–3.0\u202fg/L), and dye concentration (0.1-0.3\u202fmM) were tested to achieve maximum color removal efficiency using powder magnetite NPs. The color removal efficiencies were measured 44% at pH 9.0 and 76% at pH 3.5 for adsorption and Fenton oxidation of BR18 dye (0.1\u202fmM). Moreover, the color removal efficiencies were measured 81% at pH 3.5 and 100% at pH 6.0 for adsorption and Fenton oxidation of AR88 dye (0.1\u202fmM). The effect of hydrogen peroxide (H2O2) concentration (2.5–25\u202fmM) was also optimized and 10\u202fmM was found optimum H2O2 dosage for Fenton oxidation. However, magnetite NPs coated borosilicate glass enhanced maximum 77% and 82% color removal efficiencies for adsorption and Fenton oxidation of BR18 dye. Maximum 86% and 100% color removal efficiencies were obtained for adsorption and Fenton oxidation of AR88 dye. Stability of the powder magnetite NPs and magnetite NPs coated borosilicate glass catalyst was also investigated. The reusability of the catalyst showed that magnetite NPs coated borosilicate glass could be used at least 3 times without significant loss of activity compared to powder magnetite NPs for Fenton oxidation. The characterization of the catalyst was carried out using scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray powder diffraction (XRD), and zeta potential analyses before and after adsorption.