Open‐Pore Organic Material for Retaining Radioactive I 2 and CH 3 I

Application of ultrasound and ball milling produces micrometer‐sized crystallites of tris‐( o ‐phenylenedioxy)‐cyclotriphosphazene (TPP) that show zeolite‐like reversible sorption of I 2 and CH 3 I (methyl iodide). The thermal stability of open‐pore TPP is improved by partial loading with pyrazine. The sorption properties of open‐pore TPP are investigated by the 131 I radioactive tracer method. Comparison with activated charcoal (ACC) shows that TPP has a higher sorption efficiency for I 2 dissolved in water than ACC. In the case of a humid gaseous source of CH 3 I also, TPP exhibits better sorption properties than ACC. Partial loading of open‐pore TPP by pyrazine increases its thermal stability by 50 °C and the binding properties for retaining CH 3 I are also improved. Force‐field calculations show a difference of Δ E  ≈ 20 kJ mol –1 , making the open‐pore system less stable than the apohost.