The study investigated the adsorption behaviour of different activated carbon samples for pertechnetate under diverse conditions. Characterizations of A-CF-F and A-CF-Z samples were done using BET, FTIR, XRD, XRF and SEM–EDX methods. In batch experiments, maximum adsorption occured at pH 2, with a swift process and an optimal phase mixing time determined as 1 h for all of the samples. Analyzing experimental data using Langmuir and Freundlich adsorption models revealed coefficients of determination R² exceeding 90%. The Freundlich isotherm was found to be more suitable for describing the adsorption process.

This study focuses on the radiochemical separation and activity determination of ⁶³Ni in radioactive waste sample. A validated spectrophotometric method was employed for the chemical yield determination, replacing the traditional gravimetric approach due to its faster processing time and reduced material consumption. The spectrophotometric method was first validated using an NPL reference sample, ensuring accuracy and consistency. Radiochemical separation was conducted using ion-exchange and extraction chromatography, followed by activity measurement using liquid scintillation counting (LSC). The chemical yield was determined using both spectrophotometry and gravimetry for comparison. The average ⁶³Ni activity in the radioactive waste sample was found to be 27.9 ± 3.8 MBq/kg.

This study focuses on the usage of chitosan/hydroxyapatite composites for pertechnetate removal from aqueous solutions. Pertechnetate, a prominent radionuclide in nuclear waste, presents environmental hazards due to its long half-life and mobility. The composites, formed by intergrating hydroxyapatite into chitosan matrices, demonstrate in situ nanohydroxyapatite generation. Investigation of the adsorption process involves assessing parameters like pH, contact time, and the influence of competetive ions. This research provides valuable insights for using composites to mitigate pertechnetate contamination.

This study investigates the adsorptive properties of the filamentous fungus Aspergillus niger in both isolated and lyophilized forms for the removal of ⁸⁵Sr and ^99mTc from aqueous solutions. The adsorption process was evaluated across a range of pH values and contact times, with a focus on understanding the kinetic behavior and efficiency of each form. For ⁸⁵Sr, both forms of Aspergillus niger exhibited pH-dependent adsorption, with optimal removal efficiency occurring between pH 4 and 8. Adsorption equilibrium was achieved within 120 min, with the pseudo-second-order kinetic model providing the best fit, suggesting a chemisorption mechanism. Maximum adsorption for the lyophilized form was 68.2% at pH 4, while the isolated form reached 66.4% at pH 8. In contrast, ^99mTc adsorption was minimal across all pH levels, with less than 10% adsorption observed, indicating poor affinity for the anionic pertechnetate species. The study highlights the effectiveness of Aspergillus niger in removing ⁸⁵Sr from contaminated water, while also addressing its limitations in adsorbing ^99mTc. These findings contribute to the understanding of biosorption mechanisms for radionuclide removal in environmental applications.

This study investigates the adsorption of selected water pollutants, namely caesium and copper, by using natural zeolite of the clinoptilolite type, as well as clinoptilolites coated with MnOx, FeO(OH)-MnOx and FeO(OH). A comprehensive evaluation of these processes was conducted. The kinetics of Cs and Cu adsorption on all examined samples smoothly followed the pseudo-second-order kinetic model, with the liquid film step regarded as the slower step in both cases. The Langmuir isotherm model provided the most accurate description of Cs and Cu adsorption for all examined samples. However, when considering natural clinoptilolite and FeO(OH)-clinoptilolite systems in relation to Cu(II), the Redlich–Peterson model slightly outperformed the Langmuir model. The modification of clinoptilolite with Mn and Fe oxyhydroxides did not significantly enhance the removal efficiency of Cs compared to the unmodified sample. In contrast, the adsorption capacity, especially for MnOx-clinoptilolite, increased fourfold for Cu and other tested cations such as Pb and Zn, indicating improved efficiency in these cases.

Radioactive contamination by ¹³³ Ba and ¹³ ⁷Cs poses significant environmental risks, demanding efficient remediation strategies. This study presents the synthesis and use of innovative biochar–montmorillonite composites, produced from bamboo (BMB) and corn cob (CMB) biomass, for the removal of radionuclides from water. Physicochemical characterization confirmed successful composite formation. Crucially, the composites displayed distinct and complementary adsorption selectivities: BMB preferentially adsorbed ¹³³ Ba (qmax ≈ 0.45 mmol/g), while CMB exhibited superior performance for ¹³ ⁷Cs (qmax ≈ 0.40 mmol/g), outperforming BMB for this ion under the tested conditions. Optimal Ba ² ⁺ removal occurred at pH 4, whereas Cs⁺ adsorption was effective across a wider pH range. Pseudo-second-order kinetics governed the adsorption process for both ions on both materials, indicating chemical interactions play a key role. Isotherm analyses further elucidated the adsorption mechanisms. This work highlights the potential of designing sustainable, biomass-derived composites with tailored selectivity for efficient and targeted removal of specific radionuclides, advancing environmental remediation and nuclear waste management technologies.