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Sorption Efficacy of Weathered Basalt Rock for Metal Ions of Nuclear Importance

Background:: A safe and long-term isolation of radionuclides is crucial for efficient waste management in the nuclear fuel cycle. Clay minerals of geological origin are considered candidate barrier materials for the sequestration of nuclear waste for geological disposal applications. Objective:: The present study encompasses a systematic characterization of weathered basalt rock and the influence of its constituent clay minerals (formed mainly due to the weathering process) in the uptake of metal ions of nuclear importance, such as cesium (Cs+) and strontium (Sr2+). Methods: The structural profile of the weathered basalt has been investigated using different analytical techniques, including polarizing microscope, XRD, FTIR and EDXRF. The sorption behaviour of the rock sample for Cs+ and Sr2+ has been investigated in a comprehensive batch mode by varying the experimental conditions. The analytical findings for structure and batch sorption performance of the material have been further correlated to understand the influence of different parameters on the uptake of metal ions and the underlying mechanism. Results:: Structural analyses confirmed the presence of clay minerals viz., kaolinite, illite and montmorillonite in the sample. A comprehensive sorption performance assessment carried out in batch mode at different experimental conditions revealed that the uptake of both the metal ions was rapid and dependent on initial metal ion concentration and solution pH. The uptake of Cs+ ions was found to be higher as compared to the Sr2+ ions. EDXRF analysis confirmed the loading of Cs+ and Sr2+ on the weathered basalt. Experimental batch sorption data presented a better agreement with the theoretical Freundlich isotherm pertaining to the heterogeneous nature of the sorbent. Conclusion:: The studies highlight that the clay minerals formed by structural alteration of basalt rock upon intense weathering could be very useful in fixing the nuclear fission waste components such as Cs+ and Sr2+.

Cs promoted Ni/ZrO2-Al2O3 catalysts for dry reforming of methane: Promotional effects of Cs for enhanced catalytic activity and stability

Carbon Capture and Utilization (CCU) technologies offer a promising avenue for transforming captured CO2 into valuable products, serving as renewable fuels or precursors for high-value synthesis. This study explores the dry reforming of methane (DRM) as a viable pathway to convert captured CO2 and CH4 into syngas, achieving high equilibrium conversion through the use of suitable catalysts. Conventional nickel-based catalysts are susceptible to carbon deposition, necessitating innovative approaches to enhance their performance. A tubular microreactor was employed to conduct the reforming process at 800 °C, utilizing Cs-promoted Ni catalysts supported on 90 % Al2O3 and 10 % ZrO2-based support composition. Catalyst preparation involved the impregnation technique, and subsequent characterization employed N2-physisorption, XRD, H2-TPR, TGA, TPD, and Raman spectroscopy. The DRM reaction was systematically investigated using the Ni/ ZrO2- Al2O3 catalysts, with a specific focus on the catalytic effects of Cs promotion. Observations revealed that Cs incorporation onto the ZrO2- Al2O3 matrix led to a substantial increase in hydrogen yield and selectivity across all catalyst compositions, accompanied by a significant reduction in carbon deposition on the catalyst surface. The optimal Cs loading, determined to be 3 wt% over Ni/ ZrO2- Al2O3 catalyst, exhibited CO2 and CH4 conversions of 90 % and 87 %, respectively, with an H2/CO yield approaching 1 (0.95). This research underscores the potential of Cs-modified catalysts in enhancing the efficiency of DRM for CCU applications, providing valuable insights into optimizing catalyst formulations for improved performance in carbon transformation processes.

High Density Polyethylene/Calcium Silicate Hybrid Composite: Preparation, Characterization and <i>In-Vitro</i> Bioactivity

The high density polyethylene/calcium silicate (HDPE/CS) hybrid composites were prepared using a twin-screw extruder and shaped into test specimens using a compression molding machine. The CS loadings, limited to a total of 20 %vol, were incorporated in HDPE matrix. The morphological behavior, thermal behavior, mechanical properties and bioactivity of the composites were investigated and compared with the neat HDPE under identical conditions. It was found that poor dispersion of the CS particles was observed in the composites with high CS loadings because of only weak interaction between CS particles and HDPE. The percentage of HDPE crystallinity was insignificantly changed when adding CS particles in the HDPE/CS composites. The stiffness of the HDPE/CS hybrid composites was strongly improved and reached the maximum values of flexural and compressive moduli at 1190 MPa (35% greater than the neat HDPE) and 581 Ma (17% greater than the neat HDPE), respectively, with 15 % CS loading. The higher the CS loading, the greater the hardness of the HDPE/CS composites were seen. However, the flexural strength of the HDPE/CS composites (up to 15% CS loading) was not considerably altered. Moreover, both flexural and compressive properties were lowered with higher CS content (20%) due to the generated voids in the HDPE/CS composites. After soaking in simulated body fluid (SBF) at 36.5°C for 7–49 days, the HDPE/CS composites could induce the formation of ball-like HA aggregates covering on the composite surface, indicating its bioactivity. This research successfully prepared HDPE/CS hybrid composites with fast rate bioactivity and their modulus and strength values were within those for human trabecular bone. Therefore, the HDPE/CS hybrid composites had potentially used as bioactive materials for medical applications.

Thermal stabilization of extraframework Cs+ in zeolite 13X

Given the reversible nature of ion exchange, Cs+-exchanged zeolite 13X was thermally treated to safely retain extraframework Cs+. By thermal gravimetric-differential scanning calorimeter (TG-DSC) analysis, both endothermic and exothermic peaks, indicative of phase transitions, gradually shifted to higher temperatures at the higher surface loading of Cs+ (i.e., [Cs+]0/[NaX]0), indicating that extraframework Cs+ stabilized the zeolite framework. By thermal treatment at ≤ 800 °C, X-ray diffraction (XRD) showed that the samples with [Cs+]0/[NaX]0 = 0.5 and 5 mmol/g maintained the faujasite framework. Nonetheless, as indicated by Cs LIII-edge X-ray absorption spectroscopy (XAS) analysis, the Cs-Si(Al) interaction at ∼4.37 Å became stronger relative to the Cs-O interaction at ∼2.98 Å with the increasing treatment temperature, indicating that thermally induced dehydration caused extraframework Cs+ to migrate from spacious sites to confined (less exchangeable) sites. Thus, the redistribution of extraframework Cs+ among exchange sites was responsible for the lower leaching with the increasing treatment temperature. On the other hand, by thermal treatment at ≥ 900 °C, bulk-phase analyses such as XRD, scanning electron microscopy, and surface area measurement showed that the zeolite framework completely broke down to form non-porous phases. The XAS analysis further indicated that Cs+ was mainly incorporated into amorphous phases at 900 °C and pollucite at ≥ 1,000 °C. This was consistent with the markedly low Cs+ leaching for the ≥ 900 °C-treated samples. Since pollucite can provide the greatest retainability of Cs+, the thermal treatment leading to its formation is recommended before storing Cs+-exchanged zeolite 13X at nuclear waste repositories.

Properties enhancement of chitosan‐filled polylactic acid biocomposites using tannic acid treatment

AbstractIn this study, tannic acid‐treated chitosan (Cs‐TA)‐filled polylactic acid (PLA) biocomposites were fabricated through the melt blending and compression molding methods. The effects of Cs‐TA and their loadings (2.5, 5, 7.5, and 10) php on chemical interaction, tensile, melt processing, thermal, water absorption, and morphological characteristics were analyzed accordingly, and compared with a previously untreated PLA/Cs biocomposite. Fourier transform infrared spectroscopy analysis revealed that TA could form a cross‐linked network with Cs components as well as improving the hydrophilicity character of Cs for better interaction with PLA polymer. In addition, tensile strength and elongation at break were enhanced to the extent of ~3% and ~11%, respectively, at optimal 3% w/v TA concentration and 2.5 php Cs loading. Melt processing analysis of treated PLA/Cs‐TA demonstrated a lower stabilization torque, which implied improvement in the PLA processability. Moreover, chemical modification of Cs with TA showed a positive effect on thermal stability correlated to a higher decomposition temperature. Meanwhile, the crystallinity degree was considerably increased with TA treatment ascribed to the acceleration in crystallization process. Besides, a lower water uptake percentage proposed the Cs‐TA potential in controlling water uptake in PLA/Cs biocomposite. Indeed, the morphological analysis exhibited better filler dispersion and interfacial adhesion between Cs‐TA and PLA polymer, which justified the enhancement in all studied properties.

An in vitro investigation into targeted paclitaxel delivery nanomaterials based on chitosan-Pluronic P123-biotin copolymer for inhibiting human breast cancer cells

Targeted chemotherapy is a current research trend in cancer treatment that aims to improve the effectiveness of drug access to cancer cells. Among the vitamins, biotin has been identified as an effective targeting agent in drug delivery to cancer cells. In this work, novel biotin-conjugated chitosan-Pluronic P123, termed Cs–P123-Bio, was developed as a carrier vehicle for delivering paclitaxel (PTX) to the tumour target. The results show that Cs–P123-Bio was stable with a low critical micelle concentration (31.83 ± 4.25 μg/mL), and the encapsulation efficacy and drug loading of Cs–P123-Bio were around 94.67 ± 3.67% and 1.89 ± 0.07%, respectively. Transmission electron microscopy (TEM), dynamic light scattering (DLS) and electrophoretic light scattering (ELS) analysis indicated that the Cs–P123-Bio nanoparticles loaded with PTX formed as a spherical shape with an average diameter of 63.4 ± 0.6 nm and a positive charge. Furthermore, the PTX release profile was slow and controlled by the pH of the medium. In particular, in vitro biocompatibility assays indicated that Cs–P123-Bio exhibited good biological compatibility with a human foreskin fibroblast cell line and Cs–P123-Bio manifested good internalization efficiency in MCF-7 cells. Cs–P123-Bio also enhanced the cytotoxicity of PTX in comparison with Cs–P123. Therefore, our approach could suggest excellent potential for tumour targeting in cancer therapy.

Small to Full-Height Scale Comparisons of Cesium Ion Exchange Performance with Crystalline Silicotitanate

ABSTRACT Crystalline silicotitanate (CST) ion exchanger is planned for use in the removal of cesium (137Cs) from the aqueous phase of Hanford tank wastes in preparation for vitrification at the Waste Treatment and Immobilization Plant (WTP). Batch contact testing was conducted to assess cesium exchange kinetics at four different CST particle-size distributions. Column testing was conducted at three column sizes, small (2.5% full height), medium (12% full height), and full height, to assess Cs loading performance behavior. Testing at the small scale was compared to actual Hanford tank waste testing to verify the validity of simulant tests to reflect full-height column performance. CST particle size adjustment was essential in scaling the column dynamics down from full scale to medium and small scales. The mean (d 50) CST particle size needed to be reduced from 633 microns to 567 and 542 microns, respectively, to achieve appropriately scaled results. Based on these results, a determination of intraparticle and film-diffusion impacts on overall mass-transfer coefficients will allow future modeling of the breakthrough performance at a range of process conditions.

Response surface approach for visible light assisted photocatalytic degradation of ortho nitrophenol by magnetically separable TiO2/CS nanocomposite

Visible light induces photocatalytic degradation technology has gained increasing interest in the treatment of organic pollutants for the wastewater system. In this study, magnetically separable nanocomposite (M-TiO2/CS) was successfully synthesized with a narrow band gap (2.85 eV) than pure TiO2. A central composited design (CCD) coupled with response surface methodology (RSM) was effectively utilized to inquire about the photocatalytic degradation of ONP degradation by using M-TiO2/CS. Three independent factors including the M-TiO2/CS loading, initial ONP concentration, and pH of the solution were examined in details. Based on the results obtained from RSM analyses, an efficient pathway leading to the high degradation rate (92%) was achieved by applying 0.02 g of M-TiO2/CS dosage with 30 mg/L of a concentration of ONP at pH 6 for 180 min. The experimental results fit well with the derived response model (R2 = 0.9789). The current study proposed a cost-effective and highly efficient approach to wastewater pollution issues.

Improving Fe/Al2O3 Catalysts for the Reverse Water-Gas Shift Reaction: On the Effect of Cs as Activity/Selectivity Promoter

The conversion of CO2 into CO via the Reverse Water–Gas Shift (RWGS) reaction is a suitable route for CO2 valorisation. Fe-based catalysts are highly active for this reaction, but their activity and selectivity can be substantially boosted by adding Cs as a promoter. In this work we demonstrate that Cs modifies the redox behaviour and the surface chemistry of the iron-based materials. The metallic dispersion and the amount of metallic Fe centres available for the reaction depends on Cs loading. 5 wt. % of Cs is an optimum amount of dopant to achieve a fair activity/selective balance. Nevertheless, depending on the RWGS reactor operational temperature, lower concentrations of Cs also lead to acceptable catalytic performance. Along with the excellent activity of the prepared materials this work showcases their robustness for long-term runs and the strong impact of H2/CO ratio in the overall catalytic performance.

Aldol Condensation Reaction of Methyl Acetate and Formaldehyde Over Cesium Oxide Supported on Silica Gel: An Experimental and Theoretical Study

The catalytic performance of cesium oxide supported on three types of silica gel A-type (A-silica), B-type (B-silica) and C-type (C-silica) was tested for the aldol condensation of methyl acetate (Ma) and formaldehyde (FA) to methyl acrylate (MA). The catalysts were characterized using TEM, BET, XRD, FTIR, TG, XPS, and CO2-TPD and the reaction mechanisms were explored using DFT calculations. To obtain high selectivity of MA, appropriate amount of Cs loading is required since much higher loading of Cs leads to excessive decomposition of Ma and/or MA. On the Cs/silica, the Si–O–Cs species generated from the reaction of cesium oxide with silanol groups are the active sites as demonstrated by characterization and the DFT calculations. Silica gels with larger pore size and pore volume are preferred since these facilitate the contact of the reactants with active sites and provide higher capacity for accommodation of coke. As compared with Cs/SBA-15, Cs/B-silica seems more prospective for industrial application due to the lower cost of silica gel and even better performance.

Origin of enhanced ethylene oxide selectivity by Cs-promoted silver catalyst

Cesium (Cs) is a key promoter to improve the selectivity of Ag catalyst for ethylene epoxidation. However, there is still no consensus in the literature about the origin of enhanced ethylene oxide (EO) electivity by Cs-promoted Ag catalysts. In this paper, the role of Cs as a promoter for ethylene epoxidation on Ag catalyst is studied by both experiments conducted under industrially relevant conditions as well as density functional theory (DFT) calculations. Ag/α-Al2O3 and Ag-Cs/α-Al2O3 catalyst are prepared by excessive impregnation and evaluated for ethylene epoxidation to determine the mechanism of selectivity enhancement for Ag catalysts that contain Cs. With the optimal loading of Cs, Ag particles of uniform size are evenly distributed on the support and EO selectivity increases from approximately 72.5%–82.0% compared with the Ag/α-Al2O3. O2-TPD results indicate that Cs decreases the adsorption strength of oxygen on Ag and XPS analyses show that Cs shifts the Ag 3d5/2 binding energy to facilitate the desorption of the EO precursor to form gas EO. DFT calculations demonstrate that Cs-promotor can weaken the adsorption of atomic oxygen. Electron density of atom oxygen absorbed on silver decreases with the addition of Cs on Ag(111) thereby enhancing the electrophilic attack by atomic oxygen at the electron-rich CC bond of C2H4. Therefore, Cs lowers the activation energy for the formation of the oxometallacycle (OMC) and EO, while increasing the barrier for acetaldehyde (AA) formation, thereby leading to higher EO selectivity.

Preparation and characterization of nickel hexacyanoferrate films for the removal of cesium ion by electrically switched ion exchange (ESIX)

The method of electrically switched ion exchange (ESIX) involves the sequential application of reduction and oxidation potentials to an ion exchange film to induce the respective loading and unloading of Cs+. In this study, four films of nickel hexacyanoferrate were prepared on nickel electrodes with different preparation procedures. Films were characterized by SEM/EDX. Each film shows a different performance with regard to Cs+ separation. Scanning electron microscopy was used to characterize the modified film surfaces. Cyclic voltammetry was used to investigate the ion exchange capacity and stability. The four films show a better capacity for Cs+ separation compared to previous methods for the deposition of ESIX films. An optimal nickel hexacyanoferrate film was generated when using an applied potential of 0.2 V relative to a saturated calomel electrode (SCE) to generate the nucleation sites, followed by a 1.3 V vs. SCE potential during the growth stage of the film. This film demonstrated the highest film capacity for ion exchange initially (17.3 × 10−3 C cm−2) and again after 1000 cycles (11.1 × 10−3 C cm−2).

10000‐Fold Enhancement in Proton Conduction by Doping of Cesium Ions in a Proton‐Conducting Zwitterionic Metal–Organic Framework

Developing metal–organic framework (MOF)‐based proton‐conducting electrolytes for fuel‐cell applications is an important target that has drawn a lot of attention. A key approach involves the selective replacement of the guest species within the pores to enhance performance. The modular and crystalline nature of the MOF permits controlled introduction of such species and characterization of their compositions with high precision, a task which is very difficult to achieve in amorphous polymers. Herein, we partially replaced the protons of a zwitterionic pyridinol in Mg(terephthalate)(pyridinol) MOF 1 with Cs+ ions, which brought about a 10000‐fold increase in the proton conductivity (10–6 to 10–2 S cm–1). Interestingly, Li+ ions could not be loaded, whereas Cs+ ions with smaller hydrated ionic radii could be loaded, and the loading was controlled as a function of time. The Cs+ loading nearly halved the activation energy (from 0.35 for 1 to 0.19 eV for 1_Cs). The highest conductivities were realized for an optimal loading of Cs+ ions, which was found to be about 10 % in this case.

The effect of hydroxylation on CNT to form Chitosan-CNT composites: A DFT study

The effect of types of CNTs (pristine and hydroxylated) on the synthesis of Chitosan-CNT (CS-CNT) composites was investigated theoretically. The adsorption energy (Eads) of CS on the pristine CNT and hydroxylated CNTs (CNT-OHn, n=1–6) as well as the structural and electronic properties of said composites have been investigated. Results show that the adsorption of CS on CNT and CNT-OHn is thermodynamically favored. The Eads of CS on CNTs was calculated to be −20.387kcal/mol from electrostatic interactions. For CS adsorbed into CNT-OHn, Eads ranges from −20.612 to −37.567kcal/mol. Hydroxyl groups on CNT are the main adsorption sites for CS loading onto CNT-OHn via hydrogen-bond interactions. The CS-CNT-OH3 is the most sable composite among tested complexes. The energy gap (ΔEgap) of CS-CNT-OH3 was calculated less than pristine CNT and CNT-OH3, indicative of the composites being more reactive than that of pristine CNTs and CNT-OH3. It was proved that CS can transfer electron to the hydroxylated CNTs, thus overcoming the drawbacks of CNTs being chemically inert.

Preparation and Characterization of Natural Rubber/Chitosan Films

Natural rubber/chitosan (NR/CS) films at various NR/CS ratios were prepared here from the mixture of natural rubber latex (NRL) and chitosan solution using a solution casting method. The NRLs with and without sulfur curing agents were used. The NR/CS films were obtained after heating at 50oC for 24 hours. The NR/CS films prepared from the NRL with curing agents were further heated at 120oC for 30 min to acquire the NR networks. From swelling testing, it was found that incorporation of CS into the NR matrix gave the films with higher solvent resistance. The swelling index reduced proportionally with the increased CS loadings. Additionally, the solvent resistance of the NR/CS films was improved more once the NR was cured. In general, for every NR/CS ratio, the tensile strengths of the cured NR/CS films were higher than those of the uncured NR/CS films. After thermal aging, it was found that the tensile strength of the uncured NR/CS films decreased while that of the cured ones increased. Two thermal decomposition peaks were observed. The onset decompostion temperatures at lower and higher temperature were corresponding to the degradation of chitosan and natural rubber, respectively. The initial thermal degradation temperature of CS and NR in the NR/CS films was shifted to the higher temperature than that of the pure CS and NR, respectively.

Preparation and Characterization of Electrically Switched Ion Exchange Films

Wastewater treatment by conventional methods as ion exchange, coagulation and precipitation is very important. A relatively new method for wastewater treatment is introduced; this method is known as electrically switched ion exchange (ESIX). ESIX can be used to separate metal ion contaminants from industrial wastewater. The ESIX method involves sequential application of reduction and oxidation potentials to an ion exchange film to induce the respective loading and unloading of Cs+. The metal ion separated from the wastewater and unloaded from the electrode by modulating the potential applied to the film. This technology is superior to conventional methods (e.g conventional ion exchange) as it requires very little energy for ionic separation. In this study, two films of nickel hexacyanoferrate were prepared on nickel electrodes with different preparation procedures. Each film shows different performance in Cs+ separation. Scanning electron microscopy was used to characterize the modified film surfaces. Cyclic voltammetry was used to investigate the ion exchange capacity and stability. These two films show a high capacity and stability for Cs+ separation.

Catalytic performance and characterization of Cs–Ca/SiO2–TiO2 nanocatalysts for biodiesel production

In this research work, the transestrification (biodiesel production) of blend refined vegetable oil over novel promoted Cs–Ca/TiO2–SiO2 nanocatalysts was investigated. The effects of different mass ratios of Ca/TiO2–SiO2, loading of Cs as a promoter, calcination conditions and different operational conditions on the catalytic performance of Cs–Ca/TiO2–SiO2 nanocatalysts were studied. The best operational conditions were the methanol/oil=12/1 at 60°C with mechanical stirring of 500rpm for 2h. Characterization of catalysts was carried out by using scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), temperature programmed desorption (TPD), Fourier transform-infrared spectroscopy (FT-IR) and N2 adsorption–desorption measurements methods. The maximum biodiesel yield of 98% was obtained by using the optimal Cs–Ca/TiO2–SiO2 nanocatalyst.

Catalytic role and location of Cs promoter in Cs–Au/TiO2 catalysts for propanol synthesis from CO2, C2H4 and H2

A series of Cs–Au/TiO2 (anatase) catalysts with a Cs loading between 0wt% and 13wt% was synthesized by impregnation of Au/TiO2 and tested for CO2 conversion with C2H4 into propanol in presence of H2. Cs loading was found to significantly influence the target selectivity, which passes over a maximum over the catalysts with 4wt% and 7wt% Cs. The results of catalysts characterization by various spectroscopic techniques (HAADF‑STEM, XPS, and UV–vis) revealed that Cs species are located on both the support and the Au NP and favor stabilization of Auδ+ species. The presence of Cs was also established to increase the rate of CO insertion into C2H4; thus, improving the selectivity to propanol. The positive effect disappears for the catalysts with Cs loading above 7wt%, which possess larger Au NP (around 17nm) than the selective catalysts (1–7wt% Cs) with Au NP between 4.5nm and 7nm.

Preparation and characterization of magnetic CsH2PW12O40/Fe–SiO2 nanocatalysts for biodiesel production

The magnetic CsH2PW12O40/Fe–SiO2 nanocatalysts were prepared via combination of sol–gel and impregnation methods. The effects of different H3PW12O40/(Fe–SiO2) weight percentage, loading of Cs as a promotor and calcination conditions on the catalytic performance has been studied. It was found that the catalyst with H3PW12O40/Fe–SiO2=4wt.% and Cs=2wt.% is an optimal catalyst for biodiesel production. The activity of optimal catalyst was studied in different operational conditions. The best operational conditions were CH3OH/oil=12/1 at 60°C with mechanical stirring rate of 500rpm and the biodiesel yield reaches to 81% in 4h. Characterization of catalysts was carried out by using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM), N2 adsorption–desorption measurements methods, Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC).

Modeling of cesium sorption on biotite using cation exchange selectivity coefficients

Abstract For the modeling of cesium sorption on biotite, samples of natural biotite separated from gneissic rocks were converted into monoionic potassium, sodium, and calcium forms, and sorption isotherms for Cs/K, Cs/Na and Cs/Ca exchange were determined at pH 6 and 8 in E-4–E-8 M Cs solutions. Selectivity coefficients for Cs/K, Cs/Na, and Cs/Ca ion exchange reactions were calculated from the isotherm data, using the Gaines-Thomas convention. At Cs loadings below 1% of the total ion exchange capacity, the overall selectivity coefficient for Cs/Ca exchange was approximately five and seven orders of magnitude higher than those for Cs/Na and Cs/K exchange, respectively. Based on the selectivity coefficients, the ion exchange isotherms were modeled with the U.S. Geological Survey PhreeqC program, assuming three different types of ion exchange site: sites on the basal planes on biotite crystal surfaces with 95% site abundance, probable interlayer sites on crystal edges [frayed edge sites (FESs)] (0.02%) and third-type sites (5%), the physical background of which is unclear. Of these three types, the FES sites were superior in Cs selectivity, while the planar sites exhibited the lowest selectivity, and the third-type sites had selectivity between these two. The functionality of the model was successfully verified by modeling the Cs sorption isotherms on crushed mica gneiss rock in saline groundwater. Determination of the exchangeable ions K, Na, Ca, and Cs on the basal plane and edge surfaces by scanning electron microscopy-energy-dispersive x-ray spectroscopy (SEM-EDX) supports the results of modeling: edge sites highly prefer Cs ions and also Ca and Na ions but not K ions.