脉冲电化学氧化处理低浓度氨氮废水

Pulse current as electric source for electrochemical treatment of simulated low concentration ammonia nitrogen wastewater

大量未经处理的氨氮废水肆意排放,严重破坏生态环境和危害人类身体健康.本文设计了连续流循环装置,并采用脉冲电流替代直流电流处理低浓度氨氮废水,考察了脉冲电化学氧化法处理低浓度氨氮废水的优化工艺条件,研究了脉冲电流对氯离子添加量、能耗的影响.最佳工艺条件为:初始氨氮浓度为60 mg·L^(-1),氯离子浓度为120 mg·L^(-1),电流密度为70 m A·cm^(-2),初始pH值为9,溶液初始温度为20℃,脉冲频率为5000 Hz,占空比为50%.电解240 min后废水中氨氮的去除率达85.01%.结果表明,每处理1 t氨氮,脉冲电化学氧化法的氯离子添加量为2.35 t,直流电化学氧化法的氯离子添加量为2.73 t,脉冲比直流电化学氧化氨氮的能耗节约26.20%.采用脉冲电化学氧化法处理低浓度氨氮废水,可减少氯离子添加量,降低能耗,为电化学氧化法处理废水提供了新思路.

Large amount of untreated ammonia nitrogen wastewater is discharged unlowfally,and severely damages the ecological environment and endangers human health.In this work,a continuous loop device was built to treat simulated ammonia nitrogen wastewater by electrochemical oxidation.In order to lower dosage of chloride ion and reduce energy consumption,direct-current was replaced by pulse current.When ammonia nitrogen concentration reached 60 mg·L^（-1）,chloride ion concentration was 120 mg·L^（-1）,current density was 70 mA·cm^（-2）,initial pH was 9,initial temperature was 20 ℃,pulse frequency was 5000 Hz,duty cycle was 50%,ammonia removal efficiency achieved around85.01% after 240 min electrolysis.When 1 t ammonia nitrogen was treated by pulse current,dosage of chloride ion was 2.35 t.When 1 t ammonia nitrogen was treated by direct-current,dosage of chloride ion was 2.73 t.The energy consumption was reduced by 26.20% using pulse current.The results showed that pulse current was a prospective alternative to treat ammonia nitrogen wastewater by electrochemical oxidation.