Industrial Wastewater Reuse and Ammonium or Fluoride Removal Using Sonoelectrochemical Precipitation

Wastewater from the semiconductor industry typically contains a substantial amount of total ammonia nitrogen (TAN) and fluoride that can have adverse effects on the environment. In an attempt to remove and be crystalized, a novel sonoelectrochemical system, which is the process that combines ultrasonic and electrochemical methods. In this study, therefore, we developed a novel ultrasonic-assisted electrochemical system, and its efficacy was demonstrated. Sonoelectrochemical reaction resulted in 47.7% TAN removal efficiency at the current of 2A with 40 kHz sonication frequency. pH was the main factor for the crystallization, and an alkaline condition with a frequency of 40 kHz was optimal for TAN removal. However, temperature increase affects the TAN removal not by crystallization but by evaporation. When it comes to removing fluoride, its concentration was linearly decreased from 3000 to 1350 ppm at pH 10 by crystallization for 3 h. The precipitates were estimated as AlF3 and AIF
2
(OH). In addition, with the future development of a simultaneous operation with a scrubbing system, the cost-effective implementation of recycling industrial wastewater can be feasible.