脉冲和直流电场下阴极结构对CaCO_(3)结晶的影响

Effect of cathode structure on crystallization behavior of CaCO_(3) under pulsed and direct current electric field

电化学诱导循环水系统中的Ca^(2+)在阴极板上以CaCO_(3)的形式沉积,表现出良好的水软化效果。开展阴极板上CaCO_(3)结晶行为的研究有助于提高水软化效率。为探究极板结构和电场形式对CaCO_(3)结晶行为的影响,采用7种不同结构的阴极,分别研究脉冲电场和直流电场中CaCO_(3)的结晶行为。从宏观角度分析不同电场形式下各阴极表面的CaCO_(3)结晶速率,从微观角度分析各阴极表面的CaCO_(3)结晶性质。用高倍光学显微镜对CaCO_(3)显微结构进行表征,通过X-射线衍射仪(XRD)对CaCO_(3)结晶成分进行分析。实验结果表明,随着时间的延长,极板的结晶量增加。电场形式对碳酸钙的晶型和形貌有重要影响,在脉冲电场影响下,碳酸钙形貌变得疏松,文石质量分数增加3.15%~26.51%,10 h内Ca^(2+)去除量可提高10%,单位能耗较直流电场的能耗降低19.82%。网孔的形状和大小会影响CaCO_(3)结晶的形貌及电化学水处理装置的工作效率。综合考虑装置的单位能耗和Ca^(2+)去除量,使用网孔尺寸为1 mm×3 mm的极板时电化学水处理装置的性能最好。

Ca^(2+)in the electrochemically induced circulating water system is deposited as CaCO_(3) on the cathode plate,which exhibits good water softening effect.Studying the crystallization behavior of CaCO_(3) on the cathode plate is helpful to improve the water softening efficiency.To investigate the effects of electrode plate structure and electric field form on the crystallization behavior of CaCO_(3),seven cathodes with different structures were used to study the crystallization behavior of CaCO_(3) in pulsed electric field and DC electric field,respectively.The crystallization rates of CaCO_(3) on each cathode surface under different electric field were analyzed macroscopically,and the crystallization properties of CaCO_(3) on each cathode surface were analyzed microscopically.The CaCO_(3) microstructure was characterized by high power optical microscope,and the CaCO_(3) crystalline composition was analyzed by X-ray diffractometer(XRD).The experimental results showed that the amount of crystallization of plates increased with time.The electric field form had an important effect on the crystalline shape and morphology of calcium carbonate.Under the pulsed electric field,the calcium carbonate morphology became loose,the aragonite mass fraction increased from 3.15%to 26.51%,the Ca^(2+) removal increased by 10%in 10 hours,and the energy consumption was reduced by 19.82%compared with that of DC field.The shape and size of the mesh affect the morphology of CaCO_(3) crystallization and the efficiency of electrochemical water treatment device.Considering unit energy consumption and Ca^(2+) removal,the best performance of the electrochemical water treatment device was achieved when using plate with the mesh size of 1 mm×3 mm.