Role of raw Ilmenite nanoparticles in Rhodamine B degradation using peroxymonosulfate and graphitic carbon nitride

In this study, raw ilmenite nanoparticles (ILM) were used as a photocatalyst with peroxymonosulfate (PMS) and graphitic carbon nitride (g-C₃N₄) to remove rhodamine B dye from wastewater. The synthesized g-C₃N₄ was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Brunauer-Emmett-Teller (BET) analysis. ILM nanoparticles were characterized by XRD, FESEM, and energy-dispersive X-ray (EDX). The experiments were carried out in a rectangular Plexiglas pilot reactor with a practical volume of 3 L. The OFAT method (One Factor at a Time) optimized the influencing parameters. At pH = 3, after 180 min of treatment, 99.7% removal of 50 mg/L dye was achieved in the presence of 500 mg/L ILM, 300 mg/L PMS, and 200 mg/L g-C₃N₄. Mineralization results showed 83.2% COD and 75.8% TOC removal after 180 min of treatment. Kinetic analysis of the reactions indicated a pseudo-first-order dependence. According to the results of the scavenger study, sulfate radicals (S[Formula: see text]₄^-), hydroxyl radicals ([Formula: see text]), and superoxide radicals ([Formula: see text]₂^-) were the main active species for dye removal. The ICP-MS analysis revealed that the leached concentrations of iron, magnesium, and calcium ions were 2.6, 1.62, and 5.41 mg/L, respectively, lower than the permissible limits for wastewater discharge.