Tensides and detergents

Another large group of organic substances polluting the hydrosphere are the preparations known as tensides and detergents [115, 116]. 

Tensides are surface active substances with a capability to reduce the surface tension at an interface. In aqueous solutions they have cleansing, wetting, emulsifying, dispersing, stabilizing and frothing effects. 

The term detergent denotes washing and cleaning preparations which contain, in addition to tensides, also other additives to increase the washing and cleaning properties of the preparation. 

A molecule of tensides consists of hydrophilic and hydrophobic parts. The polar parts of the molecule are formed particularly by the sulphone, sulphonate groups or cumulated hydroxyl or etheric groups, which are all hydrophilic. The hydrophobic part is formed by aliphatic or aromatic carbon, frequently branched and substituted. From the viewpoint of dissociation capability of the polar hydrophilic group, tensides are classified into ionic and non-ionic categories  

Ionic tensides dissociate in aqueous media to generate positively or negatively charged ions. Non-ionic tensides contain a polar non-dissociated group, such as -OH, or -0-. 

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