Open-pore organic material for retaining radioactive I2 and CH3I

Application of ultrasound and ball milling produces micrometer-sized crystallites of tris-(o-phenylenedioxy)-cyclotriphosphazene (TPP) that show zeolite-like reversible sorption of I2 and CH3I (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 131I radioactive tracer method. Comparison with activated charcoal (ACC) shows that TPP has a higher sorption efficiency for I2 dissolved in water than ACC. In the case of a humid gaseous source of CH3I 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 CH3I are also improved. Force-field calculations show a difference of ΔE ∼ 20 kJ mol-1, making the open-pore system less stable than the apohost. (Abstract Copyright [2006], Wiley Periodicals, Inc.)