Radio-ruthenium (Ru) due to its existence in the form of complexes with varied oxidation state, larger fission yield and relatively long half life is an extremely troublesome nuclide during reprocessing and subsequent waste management. In the process of the concentration of high level waste (HLW), containing many nitrates of fission products and nitric acid, Ru is oxidized to volatile tetroxide RuO₄, which is reduced to its dioxide (RuO₂) at the inner surface of the equipment and is deposited there. As a result, the radiation dose of the plant equipments keeps increasing. A process was developed for the separation of Ru from HLW stream by volatilization using KMnO₄ (potassium permanganate) and O₃ (ozone) as oxidising agent and its subsequent trapping on adsorbent material polyether ether ketone pellets. Various parameters like acidity, Ru concentration, temperature, time period of reaction and type of adsorbent were studied. The sorption behaviour was examined with various isotherms like Langmuir, Freundlich and Dubinin–Raduskevich isotherms. Thermodynamics parameters were also evaluated. The results indicated that maximum volatilisation of Ru occurred in the case of KMnO₄ (98%) as compared to O₃ (53%) at low acid concentration (2 M).