Kinetics of the removal of phosphorus by ultrasound-assisted electro-coagulation

Phosphorus-containing wastewater was treated by an ultrasound-assisted electro-coagulation process.The ultrasound-assisted process improved the phosphorus removal efficiency significantly,up to 18.40% higher compared with simply stirring under the same conditions.An L16(44) orthogonal test was carried out to determine the details of the process.The four major factors were found to influence the phosphorus removal efficiency in the order of pH,initial concentration of phosphorus,electro-coagulation time,inter electrode distance.Under the optimized conditions 2 cm of inter electrode distance,pH=9,3 minutes of electro-coagulation time,and 10 mg·L -1 initial phosphorus concentration up to 99.60% phosphorus removal was achieved.The ultrasound-assisted electro-coagulation process was found to fit zero-order kinetics,and energy consumption per unit phosphorus removed was significantly lower than the stirring process.The effect of ultrasound on the process is also discussed.