Decontamination of radioactive hazardous materials by using novel biodegradable strippable coatings and new generation complexing agents.

Eight different types of complexing agents were employed for the development of new biodegradable decontamination solutions that are able to form strippable coatings after they are dispersed and allowed to dry on a variety of surfaces contaminated with 60Co, 133Ba, 137Cs and 241Am radioactive isotopes. The new generation of eco-friendly chelators with superior biodegradability, utilized for the first time in such applications, can easily replace the non-biodegradable and carcinogenic complexing agents that are still in use today, due to their decontamination performances. Furthermore, besides the complexing action over the radionuclides, the solutions contain two types of clays, Bentonite (BT) and Saponite (SP), which have the capacity to adsorb specific ions, improving the decontamination efficiency of the solutions. Our research revealed that it is preferable to replace BT with SP, due to its better dispersibility, thermal stability, next to superior ability to gel and better thermal stability (Miles, 2011). The solutions showed a decontamination factor superior to 95% for 137Cs (on all surfaces), over 90% for 60Co and 133Ba, and more than 72% 241Am (on all surfaces), except for galvanized metal plates, where lower decontamination factors were obtained: over 70% for 133Ba, maximum 41.87% for 241Am and 43.19% for 60Co.