For reactive dyeing, when the pH value is 7-9, the color difference of the product is normal, indicating that the pH range has little effect on the color difference of the product, and the presence of a small amount of alkali will not change or destroy the chromogenic group of the reactive dye molecule.
When the pH value is 8.5, the soaping color fastness and wet rubbing fastness of the fabric are level 3, which cannot meet customer requirements; when the pH value is further increased, the color fastness becomes worse. It can be seen that the alkalinity in the water increases, Affect the color fastness of dyed products.
The influent water quality of sewage reuse plants generally requires a pH value of <9 to ensure that the microbial growth of the treatment system is not harmed by alkalinity and can operate normally. The quality standards for reused water require a pH value of 85, preferably close to 7.