Activated carbons were prepared by different series of carbon dioxide and steam activation from walnut
shells for their optimal use as radioactive methyl iodide adsorbents in Nuclear Plants. The knowledge of the
most favourable textural characteristics of the activated carbons was possible by the previous study of the
commercial activated carbon currently used for this purpose. In order to increase their methyl iodide affinity,
the effect of triethylenediamine impregnation was studied at 5 and 10 wt.%. The results obtained indicated
that in both cases the adsorption efficiency is markedly improved by the addition of impregnant, which
allows the adsorbate uptake to occur not only by physical adsorption, via non-specific interactions (as in
non-impregnated carbons) but also by the specific interaction of triethylenediamine with radioactive methyl
iodide. Methyl iodide retention efficiencies up to 98.1% were achieved.