Mohsen Rezaei; Nezamaddin Mengelizadeh
Abstract
Background and purpose: In recent years, the release of persistent pollutants from wastewater treatment plants into the environment has led to health and ecosystem problems. Therefore, the aim of the present study was to activate heterogeneous peroxymonosulfate (PMS) with magnetic nanoparticles (Fe3O4) ...
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Background and purpose: In recent years, the release of persistent pollutants from wastewater treatment plants into the environment has led to health and ecosystem problems. Therefore, the aim of the present study was to activate heterogeneous peroxymonosulfate (PMS) with magnetic nanoparticles (Fe3O4) for the degradation of reactive black 5 (RB5).Materials and Methods: The present study was performed in a laboratory and column scale for RB5 dye degradation by PMS activation with Fe3O4 nanoparticles. The effect of parameters such as pH (3-11), PMS concentration (0.25-4 mM), catalyst concentration (50-500 mg/L), and solution temperature (10-50 °C) on the degradation efficiency of RB5 was investigated. Stability experiments and trapping of reactive species were studied under optimal conditions obtained from the influence of parameters.Results: Maximum dye removal efficiency (94.86%) was obtained in Fe3O4 dosage of 250 mg/L, PMS dosage of 2 mM, pH of 7, and reaction time of 60 min. In comparative experiments, Fe3O4 showed appropriate catalytic activity in PMS activation and RB5 degradation compared to the PMS process and adsorption alone. The degradation rate of RB5 improved with increasing temperature but decreased with the presence of anions in aqueous solutions due to the consumption of reactive species. Highly reactive magnetic nanoparticles showed four consecutive degradation cycles in a column reactor. Trapping experiments emphasize that both hydroxyl radicals and sulfate play an important role in the degradation of pollutants, however, sulfate radicals are a predominant species of RB5 degradation. The continuous column reactor provided 95.65%, 80%, and 50% degradation efficiencies for RB5 in synthetic, surface water, and textile wastewater samples, respectively.Conclusion: Based on the results, it can be concluded that the PMS/Fe3O4 process is a promising technology for the degradation of RB5 from aqueous solutions.