Effect of alternating electromagnetic field and ultrasonic on hard water solution and its crystallization

doi:10.11949/j.issn.0438-1157.20170856

Abstract

Abstract:

The pH and conductivity, which can reflect the physicochemical properties of hard water directly, were studied. The pH and conductivity were measured under alternating electromagnetic field, ultrasonic and their combination respectively. The variations of pH and conductivity caused by the three physical forces were discussed. In addition, the effects on the surface morphology and composition of calcium carbonate crystals caused by alternating electromagnetic field, ultrasonic and their combination were investigated by scanning electron microscope(SEM). The results show that the alternating electromagnetic field can enhance the rate of collision of positive and negative ions, promote small crystal particles forming and inhibit its volume increasing. Ultrasonic can promote the calcium carbonate precipitation forming, increase the ion migration rate in the solution, destroy the order of CO₃^2- in CaCO₃ crystals and induce the crystal surface to grow defectively. The combination of alternating electromagnetic field and ultrasonic can increase the number of small crystals, inhibit its volume growing, and increase the proportion of aragonite in the scale.

Key words: pH, conductivity, hydrolysis, nucleation, particle size distribution, SEM

摘要：

实验研究了交变电磁场、超声波及二者协同作用对硬水溶液pH及电导率的影响，并对实验过程中溶液内析出的碳酸钙晶体表面形态及晶体组成进行了观测与研究。研究结果表明：交变电磁场与超声波都能影响Ca（HCO₃）₂溶液内的离子水解平衡；交变电磁场能提升正、负离子的碰撞概率，促进CaCO₃晶体成核并抑制其体积增长；超声波能够促使CaCO₃沉淀的生成，同时增大溶液内离子的迁移速率，破坏晶体内碳酸根排列的有序性，诱导CaCO₃晶体缺陷性生长；通过SEM对最终生成的晶体形态观测可知，交变电磁场与超声波协同作用能够增加CaCO₃小尺寸晶体的数量，并抑制晶体体积生长，且能增加霰石在沉淀中的比例。

关键词: pH, 电导率, 水解, 成核, 粒度分布, SEM

CLC Number:

TQ085

ZHANG Chuanxin, HAN Yong, ZHU Lin, ZHAO Ruikuan, WU Huifan. Effect of alternating electromagnetic field and ultrasonic on hard water solution and its crystallization[J]. CIESC Journal, 2018, 69(4): 1620-1630.

张传鑫, 韩勇, 朱琳, 赵瑞宽, 吴会帆. 交变电磁场与超声波对硬水溶液及其结晶的影响[J]. 化工学报, 2018, 69(4): 1620-1630.

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