Surfactants can be used as dyeing aids and leveling agents in textile dyeing

2022-12-02 16:19:24

Surfactants are a major component of detergent decontamination formulations. Except for special applications, these products are discharged into the environment after use, either directly or after treatment in sewage treatment plants. However, the anionic surfactants that are relatively difficult to biodegrade are the main ones in detergents. The massive discharge of wastewater containing surfactants not only directly endangers the aquatic environment, kills microorganisms in the environment, inhibits the degradation of other toxic substances, but also leads to the reduction of dissolved oxygen in water, especially surfactants containing nitrogen and phosphorus. Eutrophication of water bodies. When the surfactant in the sewage entering the sewage treatment plant reaches a certain concentration, it will affect many processes such as aeration, sedimentation, and sludge nitrification.

The use of surfactant aqueous solution to improve the wettability of coal particles has important practical significance for the control of coal dust. Nonionic surfactants such as sodium o-xylylene sulfonate have been used in this regard. Glanville et al. discussed various factors affecting the wetting rate of coal dust, and the results showed that: the wetting rate measured by the Walket wetting rate experiment is mainly affected by the temperature, the size of the coal dust, and the concentration and concentration of the special surfactant used. The influence of molecular structure. In the temperature range of 10°C--40°C. The wetting rate increases approximately linearly with increasing temperature. Also, at a specific temperature, the wetting rate has a linear relationship with the increase of the average particle size of coal dust.

In the coal froth flotation process, the froth is formed by passing air into the coal slurry, so that the coal slurry contains impure, fine coal particles and water that are removed. The flotation of coal from sludge or ore depends on the wettability of the surface and the contact angle, which is the angle between the solid and the inner surface of the air bubble.   

In textile dyeing, surfactants can be used as dyeing aids and leveling agents. Surfactants can increase the solubility of dyes, enhance their penetration and adhesion on fibers, enhance their color and improve the washability of textiles.

Acid dyes are used for dyeing wool, silk and nylon. The structure of acid dyes includes a hydrophobic portion of the dye and a hydrophilic portion of sulfonic acid groups with ionic affinity. The affinity between dyes and fibers comes from the hydrophobic part of the dyes. Therefore, in order to obtain a large affinity for fibers, the dyes should have a structure that does not contain sulfonic acid groups. However, such dyes have poor solubility in water. Adding a suitable anionic surfactant will The dye can be dissolved in the dye bath to dye the hydrophilic fiber, so that the dyed product with better dyeing rate, level dyeing and deep color than the corresponding dye containing sulfonic acid group can be obtained, and the dyed product Washability can be improved by 1-2 grades.