| Summary: | 碩士 === 淡江大學 === 水資源及環境工程學系 === 88 === Electro-aggregation is a newly developed water treatment technology, which applies an electric field to re-arrange the charge of the pollutants. Particles collide in a narrow canal and rapidly aggregate to form large flocs, then float to the water surface by the adhesive of numerous small bobbles. It has been applied in many industrial wastewater treatment plants and domestic sewage treatment, which revealed the advantages include short retention time, only small space needed, and good efficiency. This study aimed to explore the phenomenon of copper ions in the electro-aggregation treatment and treatment capability influence of the anions, and its mechanisms of the functions.
An artificial wastewater was prepared with copper ions. The factors discussed included HRT, optimal conditions, initial pH, and the operation voltages, but fixed the other factors such as the layers of the reactor, the material of the electrodes, and the mode of the electrodes connection.
According to the result, electro-aggregation is an efficient way to eliminate more than 95% of copper ions under proper conditions, which is conductivity above 1.38 ms/cm, voltage above 200V, and HRT above 44 sec. The pH value of raw water and treated water will no difference (pH 4.58). There are positive correlation between the percentage of copper ions removal and electrical field intensity and HRT. Applying an appropriate conductivity is able to increase the efficiency, but the limit is 950μs/cm. Besides, through the mass balance of copper ions and redox potential evaluation, the mechanism of metal removal not only from polarization and flocculation but also includes reduction. In the research we found that, copper sulfate performs better than copper chloride at high concentration of sulfate, although the potential gradient of chloride is higher, sulfate ions have more corrosive effect than that of chloride. When processing Cu-EDTA chelate with electro-aggregation, copper ions couldn’t be removed since the strong chelating force. However, the copper ion removal could be increased to 50% when the pH was adjusted to 8.5, although the efficiency is not high but it’s fast and economic than those in the literature.
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