Production and use of novel polyanilines for treating water

The invention relates to a polyaniline, comprising aniline units and organosulphur units, characterized in that the polyaniline is doped and has a number average degree of polymerization of approximately 5 to approximately 50. The scope of the invention also includes a process for the preparation of polyaniline, wherein aniline and at least one organosulphur unit are converted to a polyaniline derivative in an oxidative, acid-catalyzed polymerization reaction. A subject of the invention is also a coated substrate which is coated with the polyaniline according to the invention and also a process for the coating of the substrate. The scope of the invention furthermore also includes a coating composition which is suitable for the coating of the substrate. The invention thus also relates to a process for the preparation of the coating composition. A subject of the invention is also the use of polyaniline which is doped and has sulphur in the main polymer chain for water treatment and/or for the purification of air and also a purification reactor for carrying out the purification process.