persulfate

Persulfate is the name for salts of the peroxydisulfate anion, S2O8^2−. The most common salts are ammonium persulfate ((NH4)2S2O8), sodium persulfate (Na2S2O8), and potassium persulfate (K2S2O8). These compounds are white, highly water-soluble crystalline solids and act as powerful oxidizing agents in aqueous media.

On heating or when activated by ultraviolet light or transition metals, the anion decomposes to sulfate radicals (SO4•−), which are strong, selective oxidants capable of degrading organic pollutants and initiating polymerizations. The persulfate ion itself is relatively stable, but its effectiveness as an oxidant increases upon activation.

Industrial production typically involves the electrochemical oxidation of sulfate solutions, generating peroxydisulfate at the anode. The resulting salts are sold as ammonium persulfate, sodium persulfate, or potassium persulfate, often as solutions or dry powders suitable for various applications.

In polymer chemistry, persulfates serve as radical initiators for vinyl and acrylate polymerizations, frequently used in emulsion and solution processes and in gel electrophoresis sample preparation (ammonium persulfate). In materials processing, persulfates are used as etchants for copper in printed circuit board manufacture. Sodium persulfate is also used as a bleaching agent in textiles and paper processing. In environmental engineering, activated persulfate is employed in advanced oxidation processes to mineralize organic contaminants and for disinfection.

Persulfates are strong oxidizers and can cause skin and eye irritation. They should be handled with appropriate PPE and stored away from reducing agents, organics, and metals. Concentrated solutions can be corrosive and may pose ignition risks if mixed with incompatible materials.