With the rapid development of the textile dye industry, the discharge of substandard printing and dyeing wastewater has become more and more serious environmental pollution. For this reason, relevant departments are also very strict about water discharge, so many companies cannot take it lightly and must strengthen discharge standards. Supervise and avoid petty losses. Polyacrylamide is usually used to treat sewage in the printing and dyeing industry. So what role does polyacrylamide play in textile printing and dyeing? What are its usage methods and precautions? Let's take a closer look at Capital Chemical.
The role of polyacrylamide in the printing and dyeing industry:
1. In the textile industry, polyacrylamide flocculant is used as a sizing agent and finishing agent for fabric post-processing, which can produce a soft, anti-wrinkle, and mold-resistant protective layer;
2. The flocculant is used as a post-treatment agent to prevent static electricity and flame retardancy of fabrics;
3. When used as a printing and dyeing auxiliary, it can make the product have high adhesion fastness and high brightness, and can also be used as a non-silicon polymer stabilizer for bleaching;
4. It has an efficient purification effect on sewage discharge from the printing, dyeing and textile industry. This is the key point.
Characteristics of printing and dyeing wastewater:
Printing and dyeing wastewater has a large amount of water. Each ton of textiles processed by printing and dyeing consumes 100 to 200 tons of water, of which 80 to 90% becomes wastewater. Textile printing and dyeing wastewater has the characteristics of large water volume, high content of organic pollutants, high alkalinity, and large changes in water quality. It is one of the difficult-to-treat industrial wastewaters. The wastewater contains dyes, slurries, auxiliaries, oils, acids and alkalis, and fibers. Impurities, sandy substances, inorganic salts, etc.
The key to coagulation treatment of printing and dyeing wastewater is to select the appropriate flocculant. The commonly used flocculants for printing and dyeing wastewater treatment mainly include aluminum sulfate, ferric sulfate, and ferric chloride in the early stage, and cationic polyacrylamide in the later stage. These flocculants are used in the treatment of printing and dyeing wastewater. The effect of treating some non-water-soluble dye wastewater is obvious, such as disperse dyes, vat dyes, sulfur dyes, COD and chroma removal rates are very high.
How to use:
1. Dissolution method: Dissolve the solid particles into an aqueous solution with a concentration of 1‰---5‰ before use so that it can be effective quickly. When adding medicine, you should adopt a gradual home medicine method and slowly add it into the water so that it can be evenly dissolved in the water.
2. Addition of dissolved solution: usually add an aqueous solution of about 0.5‰---1‰, but in the case of high concentration and high viscosity of the suspension, it is recommended to further dilute the aqueous solution to 0.1‰, then Will mix easily for full effect.
3. The molecular weight of cations is lower than that of anions, so the viscosity is weaker than that of anions. Therefore, the concentration standard of cations and non-ions is slightly higher than that of anions. (Depending on the situation, the concentration can also be appropriately adjusted according to the water concentration. If the turbidity is high, the concentration can be low. If the turbidity is low, the concentration can be appropriately increased). The recommended concentration is 5‰--1%.
Things to note:
1. When preparing PAM aqueous solution, it should be prepared in enamel, galvanized, aluminum or plastic barrels. It should not be prepared and stored in iron containers.
2. When dissolving, attention should be paid to adding the product evenly and slowly into the dissolver with stirring and heating measures. Solidification should be avoided. The solution should be prepared at a suitable temperature, and excessive mechanical shearing for a long time should be avoided. It is recommended that the mixer rotates at 60-200 rpm, otherwise it will cause polymer degradation and affect the use effect.
3. The PAM aqueous solution should be prepared immediately for use. When the solution is left for a long time, its performance will gradually decrease depending on the water quality.
4. After adding the flocculant aqueous solution to the suspension, if the mixture is stirred vigorously for a long time, the flocs that have been formed will be destroyed.