A method for obtaining non-water-soluble powders comprising antimicrobial activity and having quaternary ammonium salts adhered thereto. The invention also includes the powders thus obtained and the use thereof as antibacterial agents. The invention enables the production of non-soluble organic or inorganic powders having a particle size of 5 to 500 μm, having a quaternary ammonium salt adhered to the surface thereof and fixed on the surface. When deposited on textile materials, the powders enable bacterial and viral decontamination, by means of filtration, of polluted water or aqueous environments. Textile materials impregnated with powders according to the invention can be used in the production of breathing masks, protective garments or other items, in particular in a hospital environment. The antibacterial properties of the powders are at least twice as high as the antibacterial properties of the same quaternary ammonium salt used in isolation.
