Sodium chlorite (\(\text{NaClO}_2\)) is an inorganic chemical compound that appears as a white crystalline solid or powder. It is highly soluble in water and exhibits strong alkalinity when dissolved in solution. Sodium chlorite is primarily recognized in industrial and commercial settings for its function as a chemical oxidizing agent.
The Role as a Chlorine Dioxide Precursor
Sodium chlorite serves as the precursor for generating chlorine dioxide (\(\text{ClO}_2\)). Chlorine dioxide is an unstable, highly reactive gas that cannot be stored or shipped in large quantities, so it must be produced on-site immediately before use. This generation process involves chemically activating the sodium chlorite solution.
The activation typically occurs through an acidification step, often using an acid like hydrochloric acid or sulfuric acid, or sometimes by reacting it with chlorine gas. This chemical reaction converts the chlorite ion (\(\text{ClO}_2^-\)) into the chlorine dioxide molecule. The resulting chlorine dioxide is a broad-spectrum biocide and oxidizing agent effective over a wide range of pH levels.
Legitimate Applications in Industry and Sanitation
The oxidizing nature of the generated chlorine dioxide is widely utilized across several regulated industries for sanitation and bleaching. A primary application is in municipal water treatment, where it disinfects drinking water supplies. It is effective at eliminating pathogenic microorganisms, including protozoan cysts like Giardia and Cryptosporidium, which resist traditional chlorine disinfection.
Chlorine dioxide improves the aesthetic quality of drinking water by oxidizing iron and manganese compounds, which cause staining and discoloration. It controls undesirable tastes and odors and minimizes the formation of harmful chlorinated byproducts, such as trihalomethanes, that occur with standard chlorination.
In the pulp and paper industry, the gas generated from sodium chlorite is a standard bleaching agent for wood pulp. Using chlorine dioxide provides a high degree of whiteness while reducing harmful organochlorine compounds, making it a more environmentally responsible process. This capability is also applied in the textile industry to whiten fabrics without causing the fiber damage that other bleaches can inflict.
The food processing and agricultural sectors rely on chlorine dioxide for sanitation and preservation. It is used to wash and sanitize produce, including fruits, vegetables, and poultry, to minimize microbial contamination and extend shelf life. It also serves as a disinfectant for cleaning and sterilizing food-contact surfaces and equipment.
Misuse and Public Health Warnings
Despite its widespread and regulated industrial uses, sodium chlorite has been misused in products marketed to the public. The compound is the main ingredient in solutions promoted under names such as “Miracle Mineral Solution” (MMS), “Master Mineral Solution,” and “Water Purification Solution” (WPS). These products are typically a 28% sodium chlorite solution sold alongside a separate acid “activator,” such as citric acid.
Consumers are instructed to mix the two liquids, which intentionally generates a high concentration of chlorine dioxide, a potent industrial bleach. Regulatory bodies, including the U.S. Food and Drug Administration (FDA), have issued warnings advising the public not to purchase or drink these products for any medical purpose, as the FDA has not approved MMS for treating any disease or condition.
Ingesting the solution can lead to severe adverse health effects because it is essentially drinking bleach. Reported side effects include severe vomiting and diarrhea, which can cause life-threatening dehydration and low blood pressure. Serious consequences have included acute liver failure and other organ damage.