超声吹脱处理印染废水中氨氮的研究

采用超声吹脱技术对某印染厂印染废水中的氨氮进行了处理实验和机理探索,考察了废水初始pH值、超声功率、温度对氨氮去除率的影响。实验结果表明,当超声波功率为100W,温度为30℃,不改变原水pH值,反应150min后,废水中氨氮的去除率可以达到90.78%,与传统的吹脱技术相比提高了30%～40%。超声吹脱去除氨氮的机理主要是废水中的氨氮以游离态的形式在超声辐射产生的空化效应下高温高压热解成氮气和氢气排出,同时氨气在空化效应产生的超临界状态下传质速度加快,在吹脱条件下更易于从废水中散失。

Removal of Ammonia Nitrogen in Dyeing Wastewater by Ultrasound Stripping

Experiments of removal of ammonia nitrogen from dyeing wastewater by ultrasound stripping were carried out. Influencing factors on the removal rate of ammonia nitrogen including pH value,temperature and ultrasonic power were investigated. Results indicated that removal rate of ammonia nitrogen reached 90.78% under the optimal conditions as ultrasonic power 100W,temperature 30℃,stripping times of 150min and no changing of pH value of dyeing wastewater. Comparison with traditional stripping process,removal rate of ammonia nitrogen increased 30% ～40% through ultrasonic stripping process. Mechanism of ammonia nitrogen removal by ultrasound stripping is that ammonia molecules in the cavitations bubbles transformed into nitrogen molecules and hydrogen molecules via pyrolysis under high temperature and high pressure in the cavitations bubbles. Mass transfer speed of ammonia increases under supercritical condition emerging from ultrasonic cavitations,and easier release from wastewater by stripping.