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.

Iodine is a biologically important trace element. Its behaviour in the environment and in human metabolism is determined by the type of iodine species which takes part in chemical reactions. Knowledge of their concentrations is necessary to understand and describe the iodine reaction paths. A separation procedure is proposed for quick determination of common forms of iodine-iodide, iodate ions, molecular iodine and organoiodine (in the form of CH(3)I). The procedure consists of sequential sorption by passing the sample solution first through a solid-phase extraction cartridge to separate I(2) and CH(3)I from IO(3)(-) and I(-) then through an anion-exchange resin in a cartridge to retain the latter two species. Each loaded cartridge is eluted to separate the sorbed pair of species. Concentration determination of the resulting four solutions can be performed by standard methods, e.g. by spectrophotometry, tracer counting or with ion-selective electrodes.

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Volatile molecular iodine and organic iodine species would be generated under radiation in the gas space and sump of nuclear power plant containments during a severe accident involving core melt. Engineered and currently installed safety systems might not effectively retain highly volatile iodine species. Fast and efficient conversion to non-volatile species within the containment would lower the potential risk of a significant release into the environment and therefore, methods must be sought to reduce iodine volatility to a minimum or, ideally, to remove it completely. This paper presents the results of an experimental programme to obtain a fast and efficient reduction of highly volatile organic iodide species in aqueous solution into iodide ions.

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