New composite fibers are synthesized by in situ deposition of potassium-nickel ferrocyanide layer on the surface of modified polyacrylonitrile fibers. The data of electron microscopic and infrared investigations confirmed the formation of the ferrocyanide layer on the fibers’ surface. Composite fibers are chemically stable in both acidic and alkaline solutions, and are characterized by high selectivity for cesium ions in the presence of excess of competitive sodium and potassium ions.

Key words: caesium-137, radioactive liquid waste, composite adsorbent, polyacrylonitrile fibers, potassiumnickel ferrocyanide, selectivity, high-saline solutions