Sodium Sulfite (Na₂SO₃) 7757-83-7

Sodium Sulfite (Na₂SO₃) is a white, crystalline powder with a molecular weight of 126.04 g/mol. It is readily soluble in water and is a moderately strong reducing agent. It is primarily used as an oxygen scavenger in water treatment, a preservative in food processing, and a bleaching agent in the pulp and paper industry.

Sodium Sulfite is primarily used as an oxygen scavenger in boiler water treatment and oilfield injection systems, as a dechlorination agent in water treatment, as a food preservative and antioxidant (E221), for pulp bleaching in the paper industry, for textile bleaching and desulfurizing, in photographic developing solutions, and in chemical synthesis.

Sodium Sulfite reacts with dissolved oxygen in water according to the reaction: 2Na₂SO₃ + O₂ → 2Na₂SO₄. At ambient temperatures, the reaction is relatively slow, but at boiler operating temperatures or in the presence of a catalyst (such as cobalt), it proceeds rapidly. Each 7.88 ppm of sodium sulfite removes 1 ppm of dissolved oxygen, making it an effective and economical corrosion prevention method for boiler systems.

Yes, sodium sulfite (E221) is approved as a food preservative and antioxidant in many countries. It is widely used in dried fruits to prevent browning, in wine making to prevent oxidation and bacterial growth, and in various food products to extend shelf life. However, some individuals may be sensitive to sulfites, and products containing sulfites must be labeled accordingly. XRD Chemical supplies food-grade sodium sulfite that meets FCC specifications.

Sodium Sulfite should be stored in a cool, dry, well-ventilated area in tightly sealed containers away from heat, moisture, and acids. The product is air-sensitive and gradually oxidizes to sodium sulfate when exposed to air. Keep away from oxidizing agents and strong acids, as contact can release toxic sulfur dioxide gas. Under proper storage conditions in sealed containers, shelf life is typically 6-12 months for maximum effectiveness.