The concentration of chloride ions should keep appropriate in the coking circulating water to prevent multiple detrimental effects on the environment. Even though Friedel’s salt precipitation is a practical and economically beneficial method to remove chloride, the chloride removal of traditional method is insufficient. A modified ultrasonic method for the removal of chloride by Friedel’s salt precipitation was proposed. A number of influential elements including the ratio of reagents, reaction time, pH, temperature, stirring speed, sulfate, and fluoride, were fully investigated. The results showed that sulfate and fluoride could inhibit the chloride removal through a competitive effect with chloride. With ultrasonic enhancement, the optimal removal efficiency of chloride ions was 87.20 %, compared to 82.17 % without ultrasonic enhancement. Additionally, the reaction time was shortened by 15 minutes utilizing ultrasonic. The cavitation and mechanical disruption effects of ultrasound conjunction with precipitation can improve the efficiency of chloride removal. This study provided a theoretical foundation of ultrasonic synergistic Friedel’s salt precipitation method for chloride removal, and offered guidance for the use of Friedel’s salt with enhanced techniques in other fields.

中文翻译：

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超声波改进弗里德尔盐沉淀法去除焦化循环水中的氯离子：效率提升和机制


焦化循环水中氯离子浓度应保持适当，防止对环境造成多种不利影响。尽管弗里德尔盐沉淀是一种实用且经济有利的去除氯离子的方法，但传统方法的氯离子去除效果还不够。提出了一种改进的超声波法，通过弗里德尔盐沉淀去除氯离子。充分考察了试剂配比、反应时间、pH、温度、搅拌速度、硫酸盐、氟化物等影响因素。结果表明，硫酸盐和氟化物通过与氯离子的竞争作用抑制氯离子的去除。超声波强化时氯离子的最佳去除率为87.20%，而没有超声波强化时氯离子的最佳去除率为82.17%。此外，利用超声波将反应时间缩短了15分钟。超声波的空化和机械破坏效应与沉淀相结合可以提高氯化物的去除效率。该研究为超声协同弗里德尔盐沉淀法除氯提供了理论基础，并为弗里德尔盐强化技术在其他领域的应用提供了指导。