Sonocatalytic degradation of RhB over LuFeO3 particles under ultrasonic irradiation.

LuFeO3 particles with an average particle size of ∼200 nm were synthesized via a polyacrylamide gel route. The sonocatalytic activity of LuFeO3 particles was evaluated by the degradation of Rhodamine B (RhB) under ultrasonic irradiation, revealing that they exhibit a good sonocatalytic activity. The effects of various experimental factors including ultrasonic frequency (f), reaction solution temperature (T), catalyst dosage (Ccatalyst), initial RhB concentration (CRhB), and pH value on the sonocatalysis efficiency were investigated. It is found that the former four factors have an important influence on the sonocatalytic degradation of RhB, where the best degradation conditions are obtained to be f=60 kHz, T=40 °C, Ccatalyst=4 g L(-1), and CRhB=5 mg L(-1). The pH value has a relatively small effect on the sonocatalytic degradation of RhB compared with other experimental factors. Hydroxyl (·OH) radicals were detected by fluorimetry using terephthalic acid as a probe molecule, revealing that they are produced over the ultrasonic-irradiated LuFeO3 particles. The addition of ethanol leads to a quenching of ·OH radicals and a simultaneous decrease in the RhB degradation. This indicates that ·OH radicals are the primary active species responsible for the dye degradation.