SU1043118A1 - Method for decolouring effluents from dyeing and finishing production - Google Patents

Abstract

THE METHOD OF BLOODING OF SEWAGE DRAINAGE OF DRAINED DRAINAGE PRODUCTS, including acidification, contacting acidified runoff with iron shavings, alkalinization and settling, characterized in that, in order to increase the degree of bleaching, acidification is treated with a wastewater treatment unit, which will be drained. chlorides to achieve the oxidative n value of the 3-hdcial 900-1200 mV.

Description

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The invention relates to chemical technology, in particular to wastewater treatment, and can be used to purify wastewater from textiles and haberdashery industries. The known method of wastewater treatment of dyeing and finishing works, including the regulation of pH and the introduction of mineral coagulum l. The disadvantage of this method is the exploitation of a chemical reagent, additional contamination of the treated water with amines of iron salts, and a large amount of sediment. The closest to the proposed technical essence and the achieved result is a method of bleaching wastewater dyeing plants, including acidification, contacting acidified runoff with iron chips with simultaneous exposure to ultrasonic vibrations of alkalization and settling 2, The disadvantage of the known method is a low degree of purification waste water due to the low efficiency of using the process of dissolving iron shavings in the acid plant. The aim of the invention is to increase the degree of de-dusting of waste water systems. . . The goal is achieved by the method that includes acidification of wastewater, contact with iron shavings, lavishing and settling, acidification by treatment of wastewater in the anode chamber of the diaphragm electrolyzer in the presence of chlorides until the oxidation-reduction potential of 900-1200 mV is reached. According to a known method, a special increase in the oxidative potential is not carried out, and its value is established depending on the dose of reagent used for acidification and its oxidative properties. Since acidification of a liquid with conventional acids (sulfuric, hydrochloric, etc.) 3 does not increase more than 600 mV, in order to achieve this goal — an increase in the efficiency of use and the degree of bleaching, an additional increase in the oxidation potential is required, since at such values of potential the process of dissolving the chips proceeds with low efficiency. In the case of chemical change of the solution potential, oxidizing reagents are introduced in large quantities into the water being treated, making it difficult for its ion-molecular composition. With the value of the redox potential of 9001200 MB, there is an effective dissolution of iron shavings due to the higher potential of the electrode. Increasing the potential above 1200 mV is not economically viable, as it requires a large amount of electricity. At potential values below 900 mV, a significant decrease in iron yield occurs, which reduces the efficiency of metal dissolution. In addition, the oxidation potential is increased in the anode zone of the diaphragm electrolyzer without additional input of oxidizers or their introduction in minimum amounts, the specific concentration of chlorides, which is the increase in Eh, depends on the material of the electrodes, the current density and the time of electrotreatment. Example 1. A model solution of direct black dye 3 with a concentration of 1.00 mg / l in distilled water is subjected to purification. Purification is carried out by two methods known and proposed. By a known method, the solution is treated as follows. A 50% solution of Hj 5 is entered into the sample. The pH of the solution is 12, 2 units, contacted with iron shavings, then neutralized with alkali to a pH of 7-8 and set aside for 1.5 hours. According to the proposed method, the initial model solution is introduced Mass in the amount of 1 g / l, then treated in the anodic zone of the diaphragm electrolyzer, in contact with iron shavings, mixed with a sample from the cathode zone and defend for 1.5 hours. The results are shown in table 1. As can be seen from the proposed method, it is possible to increase the yield of iron by a factor of 2-3 compared with the known method, as well as to increase the degree of discoloration. The application of the proposed method increases the efficiency of the use of the process of dissolving iron streams in an organic medium and increases the dyspeptic spestepene. drains PRI mme R 2. To substantiate the effectiveness of the electrochemical change in the oxidation potential in comparison with the chemical change, the following experiments were carried out. Examine two types of solutions with different values of the pI and E / j. The first type of solution is prepared by adding oxidizers (50% HCE solution). The second type of solutions is prepared

in the anodic zone of the lyaphragm electrolyzer. The results are shown in table 2.

As can be seen from Table 2, the electrochemical change in Eh and pH gives a higher value than the chemical change in oxidative potential, as a result of which a greater amount of iron dissolves. The application of the proposed method allows an increase in the degree of bleaching of wastewater while reducing costs and eliminating contamination of treated water with additional reagents. .

Table 1

Claims (1)

METHOD FOR BLEACHING WASTE WATER OF DYE-FINISHING PRODUCTS, including acidification, contacting acidified runoff with iron shavings, alkalization and settling, characterized in that, in order to increase the degree of bleaching, acidification leads to the treatment of the effluent in the anode to the anode values of oxidative temperature 900-1200 mV.