5. Environment-friendly sulphur dyes
Commonly used sulphur dyes are not allergenic dyes, carcinogenic dyes and acute toxic dyes, do not contain heavy metals and organic halides that can be adsorbed. They use less salt, consume less water and energy than reactive dyes, and therefore are also sulphur dyes. One of the alternative dyes that disable dyes, especially black. However, when dyeing with sulfur dyes, it is necessary to add sodium sulfide and alkali to reduce them. Waste water contains 15% to 20% of sulfides, and the sulfur sulfide produces hydrogen sulfide odors in the production and application of severe environmental and ecological problems. pollution problem.
The Diresul RDT dye produced by the Swiss company Clariant is a 20% pre-reduced sulphur dye solution made of sodium and alkali instead of sodium sulfide and a base by using environmentally and ecologically harmless glucose and alkali as reducing agents. The sulphur content is 0.7. % to 4.0%, almost no hydrogen sulfide odor. As the new dyestuff greatly reduces the sulphide content in the waste water, the amount of water consumed is small, the waste water treatment is simple, and the oxidizing waste water can also be easily treated by using hydrogen peroxide, bromate or peroxodisulfate as the oxidizing agent in the oxidation. The company's Diresul EV new environmentally friendly sulphur dye has a sulfide content of 50 mg/L or less, a reducing agent 1/3 of the conventional amount, a significant reduction in the content of sulphides in the wastewater, and a significant reduction in the COD value of the wastewater. In addition, the company used sulphite to treat sulphur dye oxidants and introduced thiosulphate group-SSO3 Sandozol T type environmental protection sulphur dyes. Their sulphide content is virtually zero, water-soluble, and the solution is neutral. However, they have no affinity for cellulose fibers and are mainly used for leather dyeing.
In addition, James Robinson's pre-reduced sulfur dye leucosome solution, DyStar's low sulfur content sulfur dyes such as Cassulfon Black C-BRV, Cassulfon Carbon CM RV, etc. are all environmentally friendly and environmentally friendly Sulfur dyes.