This work is related to the removal of tritiated water and radioactive iodine from off-gases released during spent nuclear fuel reprocessing. Specifically, it is focused on the adsorption equilibrium of water on reduced silver mordenite (Ag0Z), which is the state-of-art solid adsorbent for iodine retention in the off-gas treatment. As the off-gases contain different gas species, including iodine and water, Ag0Z would take up iodine and water simultaneously during the adsorption process. Therefore, understanding the adsorption of water on Ag0Z is important and necessary for studying the performance of Ag0Z in off-gas treatment processes. The isotherms of water (nonradioactive water) on Ag0Z were obtained at temperatures of 25, 40, 60, 100, 150, and 200 °C with a continuous-flow adsorption system. The data were analyzed using the Heterogeneous Langmuir and generalized statistical thermodynamic adsorption (GSTA) models, and thermodynamic parameters of the isotherms were obtained from both models. Both models were found capable of describing the isotherms. Isotherms of water on the unreduced silver mordenite (AgZ) were also obtained at 25, 40, and 60 °C and parametrized by the GSTA model. Through the comparison of the isotherms of Ag0Z and AgZ, it was found that Ag0Z had a higher water adsorption capacity than AgZ. The comparison of their thermodynamic parameters suggested that the interaction of water molecules with the H+ in Ag0Z was stronger than that with the Ag+ in AgZ.

Adsorptive desulfurization is a promising alternative to hydrodesulfurization for minimizing harmful sulfur emissions from hydrocarbon fuels. Cu in Y zeolite (CuY) has shown effective sulfur adsorption, especially when paired with Ce (CuCeY). This study explores other rare earths (REs), including La, Sm, and Nd, in RE and CuRE Y and mesoporous Y (SAY) zeolites for the adsorption of benzothiophene (BT) and dibenzo­thiophene (DBT). Metal loadings on the zeolites were quantified by using inductively coupled plasma optic emission spectroscopy (ICP-EOS) and X-ray fluorescence (XRF). Characteristic adsorption modes, such as σ-bonding and π-complexation, were observed by using Fourier-transform infrared spectroscopy (FTIR). X-ray diffraction (XRD) Rietveld refinement determined that RE ions prefer the sodalite cages of Y zeolite, while Cu occupies supercage sites. Ce showed the strongest synergy with Cu compared to the other REs and the highest adsorption capacity. The results of this study provide insight into the role of RE exchanged Y on sulfur adsorption.