Xiaowei Wang

Aiming at the removal of radioactive cobalt ions from water by graphene oxide (GO), the adsorption mechanism of Co²⁺ on graphene oxide was analyzed using the quantum chemical calculation software Gaussian 16 based on density functional theory. The influence of material structure factors such as carboxyl groups, hydroxyl groups, epoxy groups and graphene sheets as well as external environmental factors such as pH, temperature and interfering ions on the adsorption effect was determined, and the influence of external environment was verified through experiments. Through calculation and experiment, it was found that the existence of oxygen-containing functional groups on graphene oxide can improve the adsorption efficiency of the material appropriately, and increasing the pH under acidic conditions was also helpful to improve the adsorption effect. The material had certain selectivity for Co²⁺, and the adsorption capacity and selectivity could be further improved when it was modified by increasing hydroxyl groups.

The efficient segregation of radioactive nuclides from low-level radioactive liquid waste (LLRW) is paramount for nuclear emergency protocols and waste minimization. Here, we synthesized Na₃FePO₄CO₃ (NFPC) via a one-pot hydrothermal method and applied it for the first time to the selective separation of Sr²⁺ from simulated LLRW. Static adsorption experimental results indicated that the distribution coefficient K_d remained above 5000 mL·g⁻¹, even when the concentration of interfering ions was more than 40 times that of Sr²⁺. Furthermore, the removal efficiency of Sr²⁺ showed no significant change within the pH range of 4 to 9. The adsorption of Sr²⁺ fitted the pseudo-second-order kinetic model and the Langmuir isotherm model, with an equilibrium time of 36 min and a maximum adsorption capacity of 99.6 mg·g⁻¹. Notably, the adsorption capacity was observed to increment marginally with an elevation in temperature. Characterization analyses and density functional theory (DFT) calculations elucidated the adsorption mechanism, demonstrating that Sr²⁺ initially engaged in an ion exchange reaction with Na⁺. Subsequently, Sr²⁺ coordinated with four oxygen atoms on the NFPC (100) facet, establishing a robust Sr-O bond via orbital hybridization.

Aiming at the removal of radioactive cobalt ions from water by graphene oxide (GO), the adsorption mechanism of Co2+ on graphene oxide was analyzed using the quantum chemical calculation software Gaussian 16 based on the density functional theory. The influence of material structure factors such as carboxyl group, hydroxyl group, epoxy group and graphene sheet as well as external environmental factors such as pH, temperature and interfering ions on the adsorption effect was determined, and the influence of external environment was verified through experiments. Through calculation and experiment, it was found that the existence of oxygen-containing functional groups on graphene oxide can improve the adsorption efficiency of the materialappropriately,and increasing pH under acidic conditions was also helpful to improve the adsorption effect, and the material had certain selectivity for Co2+, the adsorption capacity and selectivity could be further improved when it was modified by increasing hydroxyl group.

As a competitive radioactive wastewater treatment technology, electrodialysis (ED) has the advantages of low operating pressure and high cycles of concentration. In order to analyze the migration performance of radionuclides during the treatment of radioactive wastewater by ED, a radionuclide migration model was constructed based on the mass conservation law and Faraday's law with the typical radionuclide cesium as the research object. Experiments were carried out for the treatment of simulated radioactive wastewater in a small-scale ED system, and the average migration rate of radionuclides under different operating conditions was predicted by the model. The results showed that the experimental values of concentration and average migration rate of Cs(I) were significantly correlated with the calculated values of the model, in which the relative error of the average migration rate was 4.54%. The variation characteristics of Cs(I) concentration in diluted solution under different current and volume ratio conditions can be predicted by the model. The average variation rate of Cs(I) concentration decreases significantly with the increase of current and volume ratio.