Ultrasound-Enhanced Adsorption of Chromium(VI) on Fe3O4 Magnetic Particles

We have investigated the effects of ultrasound on the adsorption capacity of Fe3O4 magnetic particle sorbent for the batch removal of chromate [Cr(VI)] from simulated wastewater. Compared with stirring mode, the adsorption capacity of sorbent improved by a factor of about 6 times with ultrasonic agitation. Further experiments demonstrated that the adsorption capacity of the magnetic particles is affected by the applied ultrasonic frequency and power, which has never been reported before. It increased by about 230% when the ultrasonic frequency was increased from 40 to 59 kHz and by 310% when the ultrasonic power was increased from 40 to 200 W. Compared with the absence of ultrasound, the sorption rate increased by 1.7-2.1 times. This study provides a simple and efficient method for increasing the adsorption capacities of magnetic materials.