Magnetic extract of iron ore-derived goethite microparticles as a promising heterogeneous Fenton-like catalyst for brilliant green dye discolorization

Abstract

This research study shows that naturally occurring goethite-rich iron ore from the Tebessa region of Algeria can be positioned as a sustainable and cost-effective alternative for water treatment and natural catalyst development. This locally sourced and naturally occurring iron ore promotes a heterogeneous Fenton-like reaction for the decolorization of brilliant green (BG) dye under neutral pH conditions. The iron ore sample was collected and processed using cost-effective laboratory preparation methods. The treated iron ore sample has been thoroughly characterized in terms of composition, structure, and morphology revealing that the natural iron ore consists mainly of goethite (59%), with minor amounts of quartz, illite, and kaolinite. Further analysis showed that the studied ore exhibits mesoporous properties with a BET-surface area of 45 m²/g. UV–Vis diffuse reflectance spectroscopy confirmed the presence of iron oxide minerals, notably goethite and hematite phases. Indeed, we investigated the decolorization rate of BG dye solution using different concentrations of H₂O₂ activated with different doses of goethite-rich iron ore catalyst at 25 °C and 45 °C. During this heterogenous process, several kinetic models were examined. Preliminary experiments revealed that the optimal conditions for achieving 95% BG dye decolorization were a dye concentration of 10 mg/L, an H₂O₂ concentration of 3.0 mM, and an iron ore catalyst dose of 0.2 g/L, all within a reaction time of 2 h. This work may contribute to advance the use of natural catalysts in the challenging task of decolorization of other dyes.