Study on mechanism and kinetics of ammonia-nitrogen removal by ultrasound stripping

Key words: 
• ultrasound stripping /
• ammonia-nitrogen /
• mechanism /
• kinetics

Abstract: The experiments of the removal of ammonia-nitrogen from dyeing wastewater by ultrasound stripping were carried out,the mechanism and kinetics were studied. It was found that the presence of t-butanol had no inhibitory effect on the ozonation. It was inferred that the hydroxyl radicals were not the dominating oxidative species in the ozonation process. According to the observed product, the mechanism of ammonia-nitrogen removal by ultrasound stripping was that the ammonia molecules entered into the cavitation bubbles and transformed into nitrogen molecules and hydrogen molecules via pyrolysis at high temperature and high pressure in the cavitation bubbles. Ammonia′s mass transfer speed increased under supercritical condition emerging from ultrasonic cavitation, and easier released from wastewater by stripping. The firstorder removal kinetics of ammonia nitrogen by ultrasound stripping was observed.