Sono-enhanced degradation of dye pollutants with the use of H 2O 2 activated by Fe 3O 4 magnetic nanoparticles as peroxidase mimetic

Abstract

Sono-enhanced degradation of a dye pollutant Rhodamine B (RhB) was investigated by using H 2O 2 as a green oxidant and Fe 3O 4 magnetic nanoparticles (MNPs) as a peroxidase mimetic. It was found that Fe 3O 4 MNPs could catalyze the break of H 2O 2 to remove RhB in a wide pH range from 3.0 to 9.0 and its peroxidase-like activity was significantly enhanced by the ultrasound irradiation. At pH 5.0 and temperature 55 °C, the ultrasound-assisted H 2O 2–Fe 3O 4 catalysis removed about 95% of RhB (0.02 mmol L −1) in 15 min with a apparent rate constant of 0.15 min −1 for the degradation of RhB, being 6.5 and 37.6 folds of that in the simple catalytic H 2O 2–Fe 3O 4 system, and the simple ultrasonic US-H 2O 2 systems, respectively. The beneficial synergistic behavior between Fe 3O 4 catalysis and ultrasonic was demonstrated to be dependent on Fe 3O 4 dosage, H 2O 2 concentration, pH value and temperature. As a tentative explanation, the observed significant synergistic effects was attributed to the positive interaction between cavitation effect accelerating the catalytic breakdown of H 2O 2 over Fe 3O 4 nanoparticles, and the function of Fe 3O 4 MNPs providing more nucleation sites for the cavitation inception.