Chlorine dioxide

Chlorine dioxide (CAS 10049-04-4), also known commercially as Alcide, is a selective oxidizing biocide used in water treatment, food processing, and industrial sanitation.

Where is Chlorine dioxide used?

• Municipal and industrial water treatment: disinfects distribution systems and controls biofilm without generating trihalomethanes
• Food processing: sanitizes surfaces, equipment, and wash water for fresh produce, poultry, and seafood
• Pulp and paper: bleaching agent that brightens cellulose fibers
• Pharmaceutical and healthcare: sporicidal agent for cleanroom decontamination and hard surface disinfection
• Unlike chlorine-based alternatives, it remains effective across a broad pH range.
• Textile bleaching.
• Cleaning and disinfection of cooling towers, preventing biofilm and Legionella.
• Wastewater effluent treatment.
• Produced from acidified sodium chlorite or sodium chlorate solutions.

Good to know: Unlike chlorine-based alternatives, it remains effective across a broad pH range. The pure gas is unstable for bulk transport.

Formulation notes

• In scrubber water recirculation, a very low chlorine dioxide residual of around 0.2 ppm is sufficient to ensure odor control.
• In water it remains active as a biocide for at least 48 hours.
• More selective than ozone and chlorine, reacting only with reduced sulfur compounds, secondary and tertiary amines and some other highly reduced organic products.
• Does not react with ammonia or ammonium ions, unlike chlorine.

Typical specification

• Effective in cooling tower water at pH between 5 and 10 and needs no acid for pH adjustment.
• About 10 times more soluble in water than chlorine and does not hydrolyse in water, remaining a dissolved gas.
• Can be used either generated on site through a special process or ordered in its stabilized form (SCD), which is activated on site when needed.
• Stabilized chlorine dioxide is chlorine dioxide diluted in an aqueous solution, activated by adding an acid at the required concentration.
• When chlorine dioxide reacts with organic compounds dissolved in water at drinking water treatment plants, disinfection byproducts such as chlorite and chlorate ions are formed.

Regulatory status

• Classified under CLP index number 017-026-00-3.

Storage, packaging and handling

• Aqueous solutions containing about 1% chlorine dioxide (10 g/L) can be stored safely if protected from light and heat.
• The best way to store chlorine dioxide is in liquid form at 4 °C, where it is quite stable.
• It is rarely stored as a gas because it is explosive under pressure, and there is an explosion hazard when the concentration in air exceeds 10%.

Frequently asked questions about Chlorine dioxide

In which additional industries is chlorine dioxide applied?

It is used in the electronics industry to clean circuit boards.

What role does chlorine dioxide play in the petroleum industry?

It is used in the petroleum industry to treat sulfides.

Technical content is compiled and updated by the SoleChem product team from public technical sources; the certificate of analysis (COA) governs product-specific specifications.