Abstract.A set of experiments to study physical and chemical modification of the surface of fibers is conducted to expand the area of their application for purification of water, gas and air (including that in conditions of space). The possibility of modification of filter nozzles in the process of fiber formation by particles of coal of BAU type, copper sulfide and silver chloride is experimentally shown. The fraction of the copper sulfide powder less than 50 microns in size was crushed in a spherical mill; it was deposited on fiber at air temperature of 50 0 C and powder consumption of 0.5 g/l of air. The resulting material contained 6-18 CuS particles per 1 cm of the fiber length. An effective bactericidal fibrous material can be produced using rather cheap material -CuS and relatively cheap natural compounds of sulphides and oxides of heavy metals.