Classification paragraph by Kateryna Glevatska

Activated carbon has different types of surface groups. The most important surface groups are distinguished among three major kinds: surface compounds, which contain oxygen, surface compounds, which contain sulfur, and surface compounds, which contain nitrogen. The first type of surface groups determines hydrophilic properties of activated carbon. It can be sub-divided into four main classes, namely compounds, which have carboxylic groups, hydroxylic groups, phenolic, or carbonylic groups. The second type determines adsorptive properties of activated carbon. Surface compounds, which contain sulfur, can be sub-grouped in two main classes: surface compounds, which have sulfonic groups, and surface compounds, which have sulfoxy groups. The third type determines catalytic properties. Compounds, which contain amides or aromatic amides groups, belong to this type. So, these three main types of surface groups of activated carbon determine the main properties of it and can be sub-divided into a lot of different compounds.