Stabilized Chlorine Dioxide

Overview
Stabilized Chlorine Dioxide is a misnomer, as the product is not Chlorine Dioxide but a buffered 5% Sodium Chlorite solution.

Mode of Activation
Unlike generated Chlorine Dioxide, where the product exits the generator as concentrated, molecular Chlorine Dioxide of known concentration, stabilized Chlorine Dioxide solutions require one of the following two generation methods:

1. Pre-reaction with citric or mineral acid in a separate container before application to assure a Chlorine Dioxide production.
   
   
2. Injection of the solution on a substrate or into a medium with a pH <4 in order to possess the necessary acidity to begin a reaction with the Sodium Chlorite to produce Chlorine Dioxide.

Disadvantages of Stabilized Chlorine Dioxide

Cost
Stabilized Chlorine Dioxide is very expensive, on the order of 20 to 30 times more per pound of Chlorine Dioxide produced when compared to generated Chlorine Dioxide because:

Low Concentration
Stabilized Chlorine Dioxide is 95% water. Freight cost is high and theoretical Chlorine Dioxide available per drum is minimal.

Low Efficiency/Yield
(<15%-50%) – Of the 5% Sodium Chlorite available to produce Chlorine Dioxide from the stabilized solution, the efficiency or ability to yield Chlorine Dioxide from a 5% active Sodium Chlorite usually will not exceed 15%-50%.

Acid/Chlorite Reactions are slow. For example, HCL acid/Sodium Chlorite generators average only 65% efficiency out of a 78.5% maximum theoretical yield. Acid/Chlorite generators are designed to maximize Chlorine Dioxide efficiency by providing a reaction column, concentrated reaction chemistry and reaction time, etc. to produce Chlorine Dioxide.

Stabilized Sodium Chlorite has none of these attributes but relies entirely on the pH of the process medium and is applied at relatively low chlorite concentrations (100 to 500 mg/ as NaClO2), where the efficiency/yield is greatly reduced.

High Chlorite/Chlorite Ion Concentration
Elevated chlorite ion concentrations inhibit yeast and enzyme performance - pure Chlorine Dioxide, at the recommended dosages, does not inhibit the enzyme and is synergistic with yeast.

Dosage Accuracy
Stabilized Chlorine Dioxide solutions depend on the system process water or substrate to produce Chlorine Dioxide. Therefore, the actual Chlorine Dioxide dosage one is applying cannot accurately be determined.

Process Control
Difficult to accurately process control due to the low efficiency and high chlorite content. There is no known accurate analytical method to analyze Chlorine Dioxide production or efficiency with this chemistry specifically in high organic media.

Application Specific
Only applications that provide the proper pH and minimal or no regulatory by-product are candidates for the technology.

By-Products Fate and Waste Discharge
Since the application medium acts as the Chlorine Dioxide generator for stabilized Sodium Chlorite solutions – the actual ClO2 dosage rate, efficacy, fate, and discharge are very dynamic and can vary widely.