电絮凝过程中倒极消除极板钝化

Elimination of electrode passivation by reversing electrodes in the process of electroflocculation

针对电絮凝处理污水过程中极板易发生钝化影响电絮凝效果的问题,采用倒极方法消除了极板钝化,并通过SEM和EDS,定性、定量分析不同反应时间段极板的表面形态和元素含量的变化,研究了表面钝化层成分及含量随处理时间的变化趋势。结果表明:电絮凝处理压裂废水中Al阳极钝化层的主要成分是Al^2O^3,阴极钝化层的主要成分是CaCO^3;倒极后的阴极板表面Al^2O^3含量在20 h内由48.94%下降到18.73%,阳极板Al^2O^3含量由11.87%降低到9.28%,这表明倒极能有效消除Al^2O^3氧化膜对极板钝化的影响;对于Ca^2+含量较低的压裂废水,倒极使CaCO^3的吸附量控制在0.01%~0.34%,可有效控制极板钝化现象的发生。

To solve the problem that the electrode plate is frequently passivated which will affect the electroflocculation efficiency in the process of sewage treatment,reversing electrodes operation was used to eliminate electrode passivation.The variations of surface morphology and element contents of the electrodes at different reaction time intervals were qualitatively and quantitatively analyzed by SEM and EDS.The variation trends of composition and element content of surface passivation layer with processing time were investigated.The results show that,in the electroflocculation treatment of fracturing wastewater,the main components of passivation layers on the aluminum anode and cathode were Al^2O^3 and CaCO^3,respectively.After 20 h reversing electrodes operation,the content of Al^2O^3 on the surface of the cathode electrode decreased from 48.94%to 18.73%,and it on the surface of anode electrode decreased from 11.87%to 9.28%.The results indicate that the reversing electrodes method can effectively eliminate the effect of the Al^2O^3 oxide film on electrode passivation.When electroflocculation method was used to treat fracturing wastewater with low content of Ca^2+,the content of CaCO^3 could be controlled within the range of 0.01%~0.34%on the surface of the electrode by reversing electrodes operation,which can effectively control the electrode passivation.