Silver doped zeolite (AgX) has attracted significant attention as a good adsorbent of organic iodine (CH₃I) in the gas phase. Heat treatment of the adsorbent waste, which is composed of iodine-sorbed AgX, may be necessary for disposal, as iodine would be removed from AgX at high temperature. Therefore, the sorption and desorption behaviors of CH₃I on AgX and zeolite X (13X) were investigated. Herein, CH₃I labeled by a ¹²⁵I tracer was synthesized via isotope exchange and used for sorption experiments on AgX. From the sorption experiment results, both labeled CH₃¹²⁵I and stable CH₃I showed similar sorption behavior and nearly 100% of the CH₃I was sorbed by 5 g of AgX at a flow rate lower than 0.08 m/s. Under high humidity conditions, AgX was soaked and decreased sorption performance was observed. However, after drying the soaked AgX, sorption performance recovered to the initial state. AgX exhibited higher holding performance for iodine than 13X, as almost all of the sorbed iodine was removed from 13X up to 500 °C. In contrast, it was confirmed that removal of the sorbed iodine from AgX was not observed until 830 °C.

Experiments on gas-phase chemistry for chlorides have been conducted to clarify chemical properties of the first superheavy element, rutherfordium (Rf), Z = 104. However, adsorption enthalpies obtained in each experiment are not the same, even for those of the homologues Zr and Hf. In the present study, off-line isothermal gas chromatography was done using long-lived radioactive tracers to obtain reliable adsorption enthalpies for ZrCl₄ and HfCl₄ when adsorbed on a quartz glass surface. To simulate a column surface modified by a chlorinating reagent in on-line experiments, chromatography was also performed using a chlorinated column. A newly developed analytical method which is independent of experimental parameters and uncertain physical quantities was applied to determine the adsorption enthalpies. The obtained enthalpies for ZrCl₄ and HfCl₄ were -101.3 ± 4.0 kJ mol^-1 and -98.1 ± 3.1 kJ mol^-1 for the non-treated column, respectively, and those for the chlorinated column were -85.1 ± 4.5 kJ mol^-1 and -84.2 ± 3.3 kJ mol^-1, respectively.

Binary and ternary mixed lanthanide oxides including (La,Nd)₂O₃, (La,Eu)₂O₃, (Eu,Tm)₂O₃, (La,Nd,Eu)₂O₃, and (La,Eu,Tm)₂O₃ were synthesized at 1000 °C for 4 h, followed by characterization using X-ray diffraction (XRD) techniques before and after contact with an aqueous solution at neutral pH and 60 °C for 4 weeks. The XRD patterns of the mixed oxides confirmed a tendency to form oxide or hydroxide solid solutions depending on their mixing ratios. A complete solid solution of (La,Nd)₂O₃ underwent transformation to (La,Nd)(OH)₃, while the separated La₂O₃ + Nd₂O₃ were converted to La(OH)₃ + Nd(OH)₃. A similar trend was observed for (La,Eu)₂O₃, while (Eu,Tm)₂O₃ resulted in separate Eu(OH)₃ and Tm₂O₃ after contact with an aqueous solution because of the resistance of Tm₂O₃ to the hydration reaction. The formation of ternary oxide solid solutions and their transformation in an aqueous solution could be satisfactorily explained by the trends observed for binary mixed lanthanides.