Persulfate

Persulfates are a group of chemical compounds which contain the peroxodisulfate anion, [S_2O_8]^{2−}. They are powerful oxidizing agents used in various applications ranging from polymerization initiators to soil remediation. Persulfates include ammonium, potassium, and sodium salts, which are soluble in water and have diverse industrial and laboratory uses.

Chemistry

Persulfates are the salts of peroxodisulfuric acid (H_2S_2O_8). They are prepared industrially by the electrolysis of the corresponding sulfate in water, leading to the formation of hydrogen peroxide and the desired persulfate. The general reaction can be represented as:

2 M_2SO_4 + 2 H_2O → 2 M_2S_2O_8 + H_2

where M represents a monovalent metal, such as sodium (Na), potassium (K), or ammonium (NH_4).

Applications

Polymerization

Persulfates are commonly used as initiators in the polymerization of certain alkenes, including the manufacture of polymers such as polyethylene, polystyrene, and various acrylics. Their ability to generate free radicals under mild conditions makes them suitable for initiating the polymerization process.

Analytical Chemistry

In analytical chemistry, persulfates are used as oxidizing agents in various types of analyses, including the determination of certain metals and organic compounds. They are particularly useful in the digestion processes of water analysis, where they help in breaking down organic matter to facilitate the measurement of nutrient concentrations.

Environmental Applications

Persulfates have been explored for their potential in environmental remediation, especially in the treatment of contaminated soil and groundwater. They can degrade a wide range of organic pollutants, including pesticides, petroleum hydrocarbons, and volatile organic compounds (VOCs), through chemical oxidation.

Safety and Handling

Persulfates are strong oxidizers and pose risks of fire and explosion when in contact with combustible materials. They can also cause skin and respiratory irritation upon exposure. Proper handling and storage procedures, including the use of personal protective equipment (PPE), are essential to minimize these risks.

See Also

• Oxidizing agent
• Sulfate
• Polymerization
• Environmental remediation