Persulphates, inorganic

Antimony compounds are based on antimony, an element that exhibits both metal and nonmetal properties. Many of its compounds are toxic and corrosive, particularly the soluble salts. They include antimony iodide and antimony perchloride. Some antimony compounds decompose in water to produce toxic gases e.g., antimony sulphate decomposes to sulphur dioxide while antimony bromide produces bromine gas. 

Arsenic compounds are based on the metalloid arsenic. They are extremely toxic and include the arsenates, those that contain the AsO/ group 

Tellurium compounds are toxic. They include tellurium sulphide and tellurium dioxide. 

Dissociation of many inorganic acids yields a variety of salts. 

Chlorine forms a number of ions with oxygen, all of which are strong oxidizing agents. They react similarly to bromates, evolving chlorine gas in contact with acids. They include 

---

Persulphates (inorganic diperoxysulphates of ammonium, potassium, and sodium, and triple salt potassium monopersulphate) are used as initiators in the polymer and fibre industry, as well as other applications in other industrial sectors. 

The monomers get absorbed in micelles resulting in their swelling. Water soluble initiators are used which form free radicals. Inorganic persulphates are commonly used as initiators. The initiator diffuses into a micelle and polymerisation proceeds. As more monomer is polymerised monomers from outside the micelle diffuse inside and the process continues when another radical enters the micelle the polymerisation stops. This technique can give high Molecular weight polymers. 

Hulsmann and Hengst [41] used wet oxidation by potassium persulphate in sealed ampoules to estimate particulate organic carbon. Inorganic carbon was first removed from the sample prior to reaction with persulphate. 

Aspila et al. [60] have described a semi-automated method for the determination of inorganic, organic and total phosphorus in river and lake sediments. Total phosphorus is extracted from sediments with 1M hydrochloric acid after ignition at a high temperature (550°C) (method 1) or by digestion with sulphuric acid-potassium persulphate at 135°C in a sealed PTFE-lined Parr bomb (method 2). 

In some instances the method for carbon determination has to be modified, e.g., the determination of trace amounts of what is referred to as dissolved organic carbon in water after inorganic carbon has been removed. This type of carbon determination involves wet oxidation activated by silver ions in a solution of potassium persulphate in sulphuric acid. The oxidation of organic compounds gives carbon dioxide, which is adsorbed by molecular sieves. The molecular sieves are then heated in a flow of helium to desorb the carbon dioxide, the amount of which is measured by a TCD. The lowest concentration of organic carbon that can be measured in water is 0.2—2ppm [55]. The application of chromatographic elemental analysis to the determination of the total carbon content in water has been described [56]. 

In seawater silicon occurs predominantly as reactive silicate, the dissolved ions of orthosi-licic acid, but also as inorganic and organic fractions of suspended material, particularly originating in plankton diatoms (see Section 10.1). Die concentration of suspended silicon is very small, usually not exceeding a few /imol/L. Deating with an alkaline persulphate solution will break down these silicon complexes and convert them into reactive silicate. Only when large amounts of clay material are present a carbonate fusion is needed. 

In order to obtain beads of equal size one adds to water 0.001 wt.% of potassiiun persulphate. In practice a mixture of inorganic and organic stabilizers is often used. 

---