**1. Introduction**

Wastewaters originating from the textile, cellulose, paper, chemical, tanning, food and cosmetic industries containing dyes are a hazardous source of natural environment contami‐ nation. They are troublesome in purification process due to complex structure of dye mole‐ cules. Even small amounts of dye are undesirable as they colour water making it look unaesthetic and disturb life processes in water. Most dyes do not undergo biodegradation, deteriorate light penetration into water and inhibit photosynthesis, increase chemical and biological demand for oxygen. Some dyes are toxic and sometimes even carcinogenic and mutagenic towards living organisms and they should be carefully removed [1]. Purification of wastewaters containing dyes becomes more and more important and is aimed at avoiding potential threat for the environment and legal consequences. Decolourization of these wastewaters before their reaching water outlets is a must. Conventional methods of waste‐ waters purification do not remove colour completely. Therefore it is advisable to work out a more effective methods of wastewaters purification which would reduce the amount of discharged impurities but also contribute to recovery of water and raw materials used in technological processes. The difficulties in elaboration of both simple and economical methods of dyes removal are due to frequent changes in technology of their production as well as the use of various dyes in technological processes. In the case of impurities whose creation cannot be prevented, there should be applied highly effective technologies for their rendering harmless which can be combined into multi-stage purification systems. Such possibilities are provided by adsorption processes using, among others, ion exchangers allowing not only to separate substances dissolved based on selective interactions but also to concentrate amounts of impurities and formed closed circulation of water in the technological process.
