Design And Experimental Study On Recovery Process Of Cyanuric Acid Wastewater

Trichloroisocyanuric acid is an important organic compound, and it has strong oxidation and chlorination, widely used in disinfection, sterilization,bleaching and so on. The domestic and foreign industrial production method of trichloroisocyanuric acid is mainly chlorine method. The industrial waste water will be produced in the process that produces trichloroisocyanuric acid by chlorine method. The waste water contains trichloroisocyanuric acid, free chlorine, sodium chloride, cyanuric acid monosodium salt, dust and so on.Among them, trichloroisocyanuric acid and free chlorine that have strong oxidation must be effectively treated. Cyanuric acid and sodium chloride can be used as raw materials, so they should be recovered. At present, the disinfectant waste water treatment process can remove the free chlorine and trichloroisocyanuric acid in the mother liquor. However, there is no recovery and reuse of cyanuric acid and sodium chloride, resulting in the waste of raw materials, reducing the economy of production of trichloroisocyanuric acid.In this paper, the design and experimental study on purification process of cyanuric acid wastewater were carried out, which can effectively reduce the content of cyanuric acid in the waste liquid from 1.4g·L-1 to 0.07g·L-1. The raw material was recovered by electrolyzing the concentrated brine after separation of cyanuric acid. The process consists of four processes. First,according to the principle of cyanuric acid salting out, add sodium chloride in the wastewater, which makes the cyanuric acid separated as solid particles,and separate the majority of cyanuric acid from the waste water. Second,according to the principle of adsorption of organic compounds, the resin was used to adsorb cyanuric acid from the waste water, to achieve a certain treatment depth of cyanuric acid. Third, according to the principle of membrane separation technology, the organic compounds were separated from the waste water to further reduce the concentration of cyanuric acid. Fourth,by using the electrolysis method, the raw material was recovered by electrolyzing the concentrated brine after separation of cyanuric acid.In this paper, a new method is designed for the determination of cyanuric acid concentration, which is easy to operate, accurate and suitable for industrial application, and the accuracy of the method is verified by experiments. The results showed that the mass concentration error of cyanuric acid was less than 5%.