Volume 113, Issue 10

The separation of neptunium from high level liquid waste (HLLW) is a challenging task. The variable oxidation state of neptunium and the autocatalytic generation of nitrous acid complicate its extraction into the PUREX (Plutonium Uranium Redox Extraction) solvent. Here, three benzene centered multiple diglycolamide (DGA) ligands were explored for the liquid-liquid extraction and transport study of Np(IV) across a PTFE flat sheet supported liquid membrane. The ligands were dissolved in a 5 % isodecanol-95 % n -dodecane mixture. The transport studies were carried out keeping 239 Np tracer in the feed phase (usually 3 M HNO 3 ) and the strip phase containing 0.5 M HNO 3  + 0.5 M oxalic acid mixture, while extraction studies were usually performed from 3 M HNO 3 . Both the studies suggest that ligand L I , in which the three DGA arms are connected to the 1,3,5-positions of the benzene ring via ethylene spacers, containing ethyl groups at the other positions, showed the highest extraction and transport of Np(IV). Ligand L III , with a propyloxy ether between the ring and the DGA unit, displayed the lowest, while ligand L II , having an amido ethylene linkage between the DGA moiety and the benzene ring, showed intermediate extraction and transport behavior. The transport data suggest a highly efficient transport of Np(IV) (about 85–95 %, 5 h) with all the ligands. The permeability coefficient, diffusion coefficients and stability were also determined.

The rare earth element (REE) recovered from radioactive wastewater is of great significance for the resource sustainability, and radioactive waste minimization and management. In this study, the light REE La selected as an example, the extraction behavior of La(III) has been studied systematically using bis(2-ethylhexyl) phosphate (HDEHP) as extractant, optimizing operational parameters and elucidating the underlying mechanism for REE recovery. Optimal conditions yielded an extraction ratio exceeding 98 %, achieved at the contact time of 30 min, phase ratio of 1:1, and HDEHP concentration of 0.1 mol L −1 . Increasing HCl concentration was observed to suppress extraction, whereas elevated temperatures benefited the performance supported by thermodynamic analysis this was a spontaneous (Δ G  = −8.80 kJ mol −1 ) and endothermic process. Mechanistic investigations via FT-IR spectroscopy and slope method analysis confirmed La(III) coordination with the P=O double bond of HDEHP, forming stable complex with stoichiometric ratio of 3:1 (HDEHP:La 3+ ), and the La(III) was extracted through cation exchange. These findings not only deepen the theoretical understanding of La(III) extraction, but also provide guidelines for the REEs recovery processes in the radioactive wastewater treatment.

Terbium and thulium thin films were produced by Molecular Plating under controlled conditions to elucidate a possible influence of water and carbon dioxide present in the plating solution. Platings were made in a glovebox with variable concentration of residual water and CO 2 in a controlled inert atmosphere to study the impact on the quality of the produced thin films and on deposition yields. The morphology of the thin films was analyzed by scanning electron microscopy. The deposition yield was determined by neutron activation analysis at the research reactor TRIGA Mainz. Chemical analysis of the deposited layers was conducted using a combination of infrared, Raman and X-ray photoelectron spectroscopy. The Raman and IR spectra reveal the formation of hydroxides, oxides and carbonates. Water in the plating solution affects the quality of the thin films when its concentration exceeds 1 vol%. The presence of CO 2 leads to an increased carbonate content, which negatively influences the film quality.

Bentonite plays a significant role as a buffer backfill material in geological disposal due to its unique properties that are crucial for the safe containment of high-level radioactive waste. In this work, the impact of various factors on the adsorption of selenite (Se(IV)) by both calcium-based and sodium-based bentonite was examined using batch experiments. As a result, both types of bentonite achieve adsorption equilibrium with Se(IV) within approximately 120 h. The adsorption capacity decreases with increasing initial concentration of Se(IV), while it is positively influenced by longer contact times and higher temperatures. The partition coefficient ( K d ) exhibits a complex relationship with pH, initially decreasing, then increasing, and finally decreasing again. Additionally, ionic strength significantly affects the adsorption process. These observations suggest that Se(IV) adsorption on bentonite is pH-dependent and involves a non-spontaneous heat-absorbing process, likely a chemical reaction dominated by the ion-exchange form of chemisorption in a monomolecular layer. This process aligns well with the isothermal adsorption model and the simulated secondary kinetics of the Langmuir model. Furthermore, the adsorption of Se(IV) is notably hindered by the increased electrostatic repulsion between the negatively charged bentonite surface and the negatively charged species HSeO 3 2− and SeO 3 2− . The Fourier transform infrared spectra showed that the positions, intensities and shapes of the spectral characteristic peaks of the functional groups before and after adsorption did not change significantly.

Gamma rays are highly penetrating ionizing electromagnetic radiation, and this property has made them widely used in various industrial applications. Major areas of application for gamma rays include radiotherapy, nuclear energy, materials science, the petroleum and natural gas industry, space research, sterilization, and disinfection. However, when gamma rays interact with living cells, they can increase the formation of free radicals, leading to cell death and structural damage. Additionally, gamma rays can weaken the immune system, trigger oxidative stress and inflammation, and cause pain. In this context, there is a significant need for protective substances to minimize the biological damage caused by gamma radiation exposure. Zingerone, one of the active compounds in ginger, has strong antioxidant properties and can limit cellular damage by combating free radicals. Ibuprofen, with its anti-inflammatory properties, may help reduce inflammation and oxidative damage. Sulfasalazine, on the other hand, regulates excessive immune responses, preventing the development of inflammatory diseases such as rheumatoid arthritis and spondylarthritis, and can also limit the negative effects of gamma radiation on the immune system. This study investigates the potential of zingerone, ibuprofen, and sulfasalazine as active ingredients for developing protective drugs against gamma radiation. The interactions of these compounds with gamma rays were explored both theoretically and experimentally. Key absorption parameters for gamma rays, such as mass attenuation coefficient, linear attenuation coefficient, half-value layer, mean free path, and effective atomic number, were calculated using the WinXCom program. Gamma radiation absorption experiments were conducted using radioactive sources, including 100 mCi of Am-241 (with a specific activity of 1.27 × 10 11 Bq/g or 3.44 Ci/g), 13 Ci of Ba-133 (with a specific activity of 629 GBq/g or 13 Ci/g), and 0.081 μCi of Cs-137 (with a specific activity of 3.2 × 10 12 Bq/g). These sources emit photons in the energy range of 0.0139 MeV–0.6620 MeV, and the measurements were carried out using an ultra-high purity germanium (HPGe) detector. The experimental and theoretical data were compared. The results show that all samples have the capacity to absorb gamma radiation. Notably, sulfasalazine (DA3) exhibited a higher gamma radiation absorption capacity than the other compounds. This finding suggests that the investigated compounds can be used as active ingredients in the development of protective drugs against gamma radiation.

This study presents the preparation of acrylonitrile butadiene rubber (NBR) composites loaded with different concentrations of electromagnetic radiation shielding materials like magnetite and manganese dioxide. The composites were subjected to electron beam irradiation at 50 kGy and characterized using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) tools. The hybrid fillers showed a strong interaction with the NBR rubber matrix, improving mechanical properties like tear strength. Electrically conducting of these filler materials that loaded NBR rubber matrix find a lot of attentions for electromagnetic shielding materials. All prepared samples were measured using vector network analyzer (VNA) with aid of an X-band wave guide to evaluate its performance as an electromagnetic interference (EMI) shielding material. The results showed that all samples improved shielding properties and can be used as low-cost, lightweight, and good-performance shielding materials.

This study examined the BaO–PbO 2 –B 2 O 3 –Pr 6 O 11 glasses’ gamma radiation shielding characteristics, harnessing the Phy-X program for reporting the attenuation and penetration parameters at energies within the 0.122–0.964 MeV range. With increasing energy, the linear attenuation coefficient values exponentially reduce in the 5.854–0.278 cm −1 (0Pr 6 O 11 sample), 6.498–0.292 cm −1 (1Pr 6 O 11 sample), 7.106–0.307 cm −1 (2Pr 6 O 11 sample), and 7.686–0.320 cm −1 (3Pr 6 O 11 sample) ranges. The results at all selected energies reveal that PbO 2 , BaO and Pr 6 O 11 incorporation causes increased LAC values. The half value layer values highlight a greater photon interaction possibility at higher PbO 2 , BaO and Pr 6 O 11 concentrations. The minimum HVL is found at 0.121 MeV of 0.118 and 0.090 cm for the 0Pr 6 O 11 and 3Pr 6 O 11 samples, respectively. The mean free path results reveal greater photon shielding at 0.121 MeV, while this reduced with increased radiation energy. The radiation protection efficiency (RPE) values increase with higher PbO 2 , BaO and Pr 6 O 11 content and decrease with increase in the energy. 3Pr 6 O 11 glass sample has the maximum RPE and thus is the optimum glass for radiation shielding purposes.

New types of radiation shielding borate glasses containing ZnO in micro- and nano-sized forms were fabricated. The effect of incorporating 20 μm (micro ZnO), 20 nm (nano ZnO), and a combination of 10 μm + 10 nm ZnO on the radiation shielding parameters was experimentally reported. The results showed that the glasses with micro ZnO have the smallest linear attenuation coefficient (LAC) at all energies, followed by the glasses with nano ZnO, and lastly the best shielding performance or highest LAC those with both micro and nano ZnO. The decrease in LAC for the micro-ZnO sample is due to the irregular distribution of particles within the glass matrix, and that the improvement in the nano- or (micro + nano) glass samples reflect an improvement in the internal structure and radiation attenuation efficiency. The half value layer (HVL) at 0.059 MeV is 0.042 cm for the glass with micro ZnO particles, 0.039 cm for the glass with nano-ZnO, and 0.037 cm for the glass with the micro + nanoparticle sample. The HVL results confirm that the combination of micro and nanoparticles is most effective at reducing the necessary size of the glass shield through a more uniform packing of the ZnO particles within the glass sample. The radiation shielding efficiency (RSE) is highest at 0.059 MeV and equals 100 % for all samples prepared with a thickness of 1 cm. The differences between samples with a lower thickness appear. For example, at 0.3 cm, the RSE was 99.25 %, 99.55 % and 99.71 % for micro, nano and (micro + nano) samples, respectively, indicating that at very low energies the glass attenuates essentially all of the incoming photons. At higher energies, the RSE begins to decrease and varied between 18.05 % at 0.662 MeV and 11.35 % at 1.333 MeV.