Synthesis of ternary Polyaniline/Bi2S3/NiFe2O4 nanocomposite: as a magnetic separable, reusable, and visible light-responsive photocatalyst for degradation of indigo carmine dye

Due to a worldwide shortage of water resources, removing dye pollutants from water is widely regarded as a crucial concern. Consequently, photocatalysis is gaining recognition as a viable approach for the treatment of water. In this study, Polyaniline/Bi₂S₃/NiFe₂O₄ nanocomposite is prepared by the coprecipitation method for the photodegradation of indigo carmine (IC) dye. The prepared samples are then examined via FTIR, XRD, TEM, SEM, VSM, PL, and DRS techniques. In the second part of the research, a thorough examination is conducted on the influence of photocatalyst dosage (0.1–1 g/L), initial concentration and pH (2–9), of dye solution (10–50 mg/L) on the photocatalytic degradation of IC dye under visible light irradiation. Results indicate that reducing pH, increasing time, and dosage of photocatalyst indicate a positive impact on dye removal efficiency. So that in the optimal conditions of pH = 2 with 0.5 g/L of photocatalyst in 10 mg/L of pollution solution, the highest efficiency of photocatalytic removal of IC dye is obtained 96.01%. In addition, the nanocomposite maintains 78.19% activity after four consecutive cycles. Based on the photocurrent and EIS Spectroscopy analyses, the enhanced photocatalytic efficiency of the Polyaniline/Bi₂S₃/NiFe₂O₄ nanocomposite can be ascribed to the expeditious separation and migration of electron–hole pairs and a lower charge transfer resistance. Finally, using the simplified Langmuir–Hinshelwood equation (first-order model) in kinetic studies recommended that the employed model is appropriate for precisely explaining the experimental data accurately.