Removal of Ammonium and Fluoride From Industrial Wastewater by Sonoelectrochemical Precipitation

Wastewater from the semiconductor industry typically contains substantial amounts of total ammonia nitrogen (TAN) and fluoride that can have adverse effects on the environment. The present study examined the efficacy of a sonoelectrochemical system which applies ultrasonic waves to an electrochemical process in removing these species from wastewater. Application of the sonoelectrochemical process with a current of 2 A, and a sonication frequency of 40 kHz to synthetic wastewater resulted in a TAN removal efficiency of 52.2%. pH was the main factor affecting TAN crystallization, with alkaline conditions in combination with a sonication frequency of 40 kHz being optimal for TAN removal. In terms of fluoride removal, application of the sonoelectrochemical process for 1.5 h achieved a removal efficiency of 98% at pH 7. The main precipitates obtained were Al-F complexes. The present findings indicate that the sonoelectrochemical process is a feasible and cost-effective approach for use in the recycling of industrial wastewater