Sodium sulfite

Sodium sulfite (CAS 7757-83-7), also known as sodium sulphite and approved as food additive E221, is an inorganic reducing agent and antioxidant used across food processing and water treatment. Its oxygen-scavenging capability makes it a practical choice for preserving product quality and controlling oxidative degradation in both aqueous systems and dry formulations for industrial manufacturing.

In food and beverage production, E221 functions as a preservative and antioxidant in dried fruits, wines, and starch products, inhibiting browning and microbial growth during the storage process. Water treatment operations use it to dechlorinate process water and boiler feedwater, neutralizing residual chlorine before discharge or reuse to protect sensitive equipment and the environment.

Pulp and paper manufacturers apply it in kraft and sulfite pulping processes to delignify wood fiber and control brightness. In textile and leather processing, it acts as a reducing agent. It is also used as a stripping agent to correct uneven dyeing in dyebath preparation. Sodium sulfite is supplied as a white crystalline powder or granules in the anhydrous form for easy handling.

Standard grades include food-grade (FCC, E221), pharmaceutical-grade (USP, BP), and technical-grade for industrial applications. Packaging typically ranges from 25 kg bags to bulk quantities. Depending on grade and application requirements, this chemical ensures stability and performance. It remains a critical component for manufacturers seeking reliable antioxidant and dechlorination solutions.