Background :Control of radioactive emissions from nuclear power plants , particularly radioactive iodine compounds before discharge to the environment is important . 

  Methods : In this study, methyl Iodide vapour adsorbtion capacity was evaluated on the basis of the activated carbon and TEDA (tri ethylene di amine), and HMTA (Hexa methylen tetra amine) impregnated activated carbon bed .

  Results : The amounts of chemisorption and physical adsorption of methyl iodide were measured in different humidity levels (0 & 65%) for base and HMTA,TEDA-impregnated activated carbons. The physical adsorption of methyl iodide in the presence of water vapor was low. The significant amount of chemisorption even in high humidity conditions confirmed the effectiveness of TEDA-impregnation for trapping methyl iodide permanently.