Investigation on the Efficient Removal of U(VI) from Water by Sulfide Nanoscale Zero-valent Iron

In recent years, uranium (U(VI)), a radioactive contaminant, has been widely used in industrial production and military fields. Although the industry has developed, its discharge in water poses a serious threat to the natural environment and biological health. In order to solve this problem, in this study, we prepared sulfide nano zero-valent iron (S-NZVI) material by liquid-phase reduction using NaBH4, FeSO4 center dot 7H(2)O and Na2S2O4 as main materials in N-2-filled glove box, and applied them to U(VI) removal from water. First of all, serial microscopic characterization techniques were adopted to explore the surface morphology and physicochemical properties of S-NZVI. The results showed that the S-NZVI particles are less agglomerated and more stable compared to nano zero-valent iron (NZVI). Subsequently, we investigated the effects of reaction time, temperature, pH, and background ion concentration on the removal of U(VI) by S-NZVI through macroscopic batch experiments. The consequence indicated that the maximum removal of U(VI) by S-NZVI at room temperature (20 degrees C) could reach 562.5 mg.g(-1), and the reaction equilibrium could be received within 100 min. And more importantly, the eliminated process of S-NZVI is consistent with Langmuir single-molecule layer adsorption model, and the conditions for optimal performance were at ambient temperature (20 degrees C) and pH=7 similar to 8. Combined with the results of macroscopic experiments and X-ray photoelectron spectroscopy (XPS) analysis, the removal mechanism of U(VI) by S-NZVI may be attributed to the synergistic effect of adsorption and redox reaction. In addition, S-NZVI can be separated from water rapidly by external magnetic field due to its magnetic property, which is convenient for material recycle and reutilization. In conclusion, this study has prepared a facile, recyclable, and efficient material for U(VI) decontamination, which may play a significant role in the future of environmental protection, nuclear waste remediation, and other related fields.

Automated summary

A new material, sulfide nano zero-valent iron (S-NZVI), was prepared and applied for removal of uranium (U(VI)) from water. Through experiments and analysis, it was found that S-NZVI has high efficiency in U(VI) removal, with a mechanism attributed to adsorption and redox reaction, and advantages in rapid separation and recyclability.