超声-电凝聚除磷技术及动力学分析

采用超声辅助电凝聚技术处理含磷废水,研究该技术的可行性及其特点.通过对比实验表明,在相同实验条件下,超声辅助电凝聚除磷效率比磁力搅拌电凝聚除磷效率高18.40%.进行L16(44)四水平四因素正交优化试验,结果表明,超声-电凝聚除磷的影响因素主次关系依次为pH、磷初始浓度、电混凝时间、电极间距.在最优组合工艺条件下,即电极间距为2cm,pH为7,电混凝时间为3min,磷初始浓度为10mg·L-1,磷的去除率达到99.60%.初步分析了超声-电凝聚除磷的机理以及超声在电凝聚除磷过程中的作用.动力学分析表明,超声-电凝聚除磷符合零级反应动力学规律.能耗估算表明,超声-电凝聚技术除磷的单位磷能耗明显低于磁力搅拌电凝聚除磷的单位磷能耗.

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.