Sodium Hydrosulfite or Sodium dithionite (Na2S2O4 CAS: 7775-14-6) is commonly known as "baoxianfen" in China, it means "insurance powder". This name comes from the printing and dyeing industry. Because sodium dithionite can ensure that no fiber of any material will be damaged when bleaching clothing materials, it is suitable for various fabrics, so it has obtained the name of "insurance powder".
Sodium dithionite is not only used in the printing and dyeing industry, but also in the bleaching of food and pulp. In many countries, sodium dithionite is a legal food bleaching agent, preservative and antioxidant.
Sodium dithionite cannot be used under acidic conditions, because under such conditions, it will not only show reduction ability, but also decompose to produce toxic sulfur dioxide gas.
According to different needs, sodium dithionite can produce different degrees of bleaching, which can be achieved by adjusting the pH of the solution.
In a neutral environment, sodium dithionite has a weak reducing ability, which can remove most of the color of non reducing dyes on the clothes and retain the color of the clothes itself.
In alkaline environment, sodium dithionite has strong reducing ability, which can remove the color of clothes and realize complete bleaching.
Sodium dithionite is chemically unstable and should be carefully kept, avoiding and contacting oxygen, water, high temperature, acidic substances. Protection should be taken when dealing with sodium dithionite accidents to avoid direct contact as much as possible.
