Production of Hydroxyl Free Radical, the Main Mechanism for Removing Steroid Hormones by Ultrasound

One of the new methods for elimination or destruction of estrogen hormones is ultrasound irradiation. The aim of study was to determine the main mechanism of steroid hormones removal by ultrasound.
In this study, estrogen and 17 beta estradiol irradiated with ultrasound at different frequencies, powers, and exposure times in two cases: with and without butyl alcohol in a batch mode cylindrical reactor made of plexiglas in the amount of 1 liter. Residual concentrations of hormones were measured by solid phase extraction and Gas chromatography-Mass chromatography (GC-MS).
The result showed that ultrasound has high ability on removing hormones E1 and E2 (between 56.3% to 79.2%). Also after adding butyl alcohol which is free radical scavenger, the removal efficiency of both hormones greatly reduced but didn’t reach to zero, so the main mechanism of hormones removal was hydroxyl free radical production however the cavitation phenomenon played a role in the removal.
Due to the high efficiency of ultrasound for the removal, as well as defects in other removal methods, it is suggested that researchers study in optimizing the effective parameters on it and technical and economical comparison with other removal methods.