The use of Fe₃O₄/MnO₂-Ag nano-photocatalyst to remove dyes from real wastewater samples under visible light

There are many challenges to advance the industrial applications of photocatalysts such as the difficulty of using ultraviolet waves in the photocatalyst applications. The present paper aims to evaluate the use of Ag additive on the photocatalyst degradation efficiency of Fe₃O₄/MnO₂ in the case of a real wastewater sample. In this study, Fe₃O₄/MnO₂-Ag nano-photocatalyst is synthesized and utilized for the removal of dyes from real wastewater under visible light. In this regard, important variables including pH, COD (as an index of dye concentration), Ag amount, and the amount of photocatalyst usage were concerned. For evaluating the microstructure and purity of the synthesized photocatalyst, TEM, SEM, FESEM, XRD, and EDS analysis were utilized. Response Surface Methodology (RSM) was applied to designing the experiments, evaluating the interaction effects, and optimizing the process factors by using Design Expert software V3 software. Based on ANOVA results, the high predictive capability of the utilized model was confirmed. The results of analysis and experiments demonstrated that, based on TEM and SEM micrographs, the nanocomposite consists of semi-spherical Fe₃O₄ particles with a clear MnO₂ layer. In addition, the synthesized Fe₃O₄/MnO₂-Ag nano-photocatalyst showed to have suitable optical and photocatalysis properties. In addition, it exhibited high photocatalytic activity, with an efficiency of more than 80% even after 6 consecutive runs. In addition, the use of Ag enhanced the photocatalytic performance and contributed to the good recovery capability of the nanocomposite.