Sodium Bisulfite Supplier in South Africa

What Is Sodium Bisulfite?

Sodium bisulfite (NaHSO₃) is a partially neutralised sulfite salt supplied as a 38–40% aqueous solution or as a white to yellowish powder, depending on specification. It is in equilibrium with sodium metabisulfite (Na₂S₂O₅) in solution and functions as a mild reducing agent, antioxidant, and SO₂ source. Its broad-spectrum activity against yeasts, moulds, and bacteria, combined with regulatory approval as a food additive, makes it one of the most widely used chemical preservatives in food, beverage, and water treatment applications.

Conservazione di alimenti e bevande

Sodium bisulfite is used as a food preservative and antioxidant (E222) in fruit juices, wine, dried fruit, beer, and jam, where it inhibits microbial growth and enzymatic browning. In winemaking, it is one of the primary additives for protecting wine against oxidation and spoilage organisms during fermentation, storage, and bottling. In dried fruit production, sulfite treatment preserves colour and extends shelf life. Its concentration must comply with regulatory limits for SO₂ content in the applicable food category.

Water Treatment & Dechlorination

Sodium bisulfite is one of the most widely used dechlorination agents for drinking water, process water, and wastewater. It reacts rapidly with residual free chlorine and chloramines under mild conditions, neutralising disinfection residuals before discharge or further treatment. In boiler feed water treatment, it is used to scavenge dissolved oxygen, preventing corrosion in steam-generating systems. The reaction is fast and reliable, making NaHSO₃ the preferred choice for continuous online dechlorination.

Textile & Industrial Processing

In the textile industry, sodium bisulfite is used as a stripping agent and reducing agent in vat and sulphur dye application, and for discharging colours in discharge printing. It is used in the reduction of dyes, bleaching agents, and chromium compounds in spent plating baths. In the pulp and paper industry it is a delignification chemical, and in photography it is used as a preservative in developer solutions. Industrial grades are supplied in bulk for continuous process applications.