A new nanosphere was devised to address uranium contamination, consisting of a magnetized hollow ferro-ferric oxide (h-Fe3O4) center and a phosphate-modified layered double hydroxide (phos-LDH) cover in a study available as a pre-proof in the journal Separation and Purification Technology.
Study: Hollow Fe3O4 nanospheres covered by phosphate-modified layered double hydroxides for the removal of uranium (VI) from water and soil. Image Credit: H_Ko/Shutterstock.com
The Threat Posed by Nuclear Pollutants
The worldwide energy situation has worsened due to the exhaustion of fossil fuels like coal and oil, leading to an increase in the need for nuclear energy. However, radioactive substances created and discharged into the ecosystem by the nuclear sector (like 235U, 239Pu, and 137Cs, among others) would ruin their ecology, disrupt the food web, and negatively impact many organisms.
The most visible disaster was the major release of nuclear waste (like uranium) at the Fukushima Daiichi nuclear power facility on March 11, 2011, which posed a significant hazard to human health. The uranium content in nearby soil and waterways has been found to be substantially greater than the permissible limit.
Once extremely poisonous and long-lasting radioactive uranium enters organisms, powerful internal radiation causes irreversible lifelong harm. As a result, it is critical to develop efficient methods for purifying radioactive uranium contaminants in the ecosystem.
Purification of U(VI)-Contaminated Water and Soil
Generally, U(VI) is the most common uranium contaminant in water and soil. A number of processes, including adsorption, flocculation, catalysis, chemical precipitation, and electrodeposition have been used to purify radiological uranium-containing water.
In contrast with other methods, the inexpensive, highly effective adsorption approach holds the most promise. As a result, the creation of highly effective U(VI) adsorbent materials is advantageous.
Adsorbents including LDH/GO, Fe3O4@Au/PDA, Fe/N-C-700, LaPO4, and polypyrrole (PPy) have recently been synthesized and utilized for purifying U(VI)-polluted water. In comparison with U(VI)-polluted water, U(VI)-contaminated soil is more detrimental to the ecosystem over an extended period of time and is more challenging to purify.
Due to limits in adsorptive performance and separating procedures, most existing adsorbents have difficulty removing radioactive particles like U(VI) from the soil. To close this gap, effective adsorbents and accompanying segregation methods for treating U(VI)-contaminated soil are required.
Using Phosphate and LDHs in Conjunction
Since U(VI) is a hard acid, it has a strong attraction for phosphate groups. When phosphate is added to U(VI)-contaminated water, it produces uranyl phosphate, which may be collected in the form of precipitates quickly by changing pH and then cleansed by separating.
The phosphate supplied to the water body, on the other hand, will increase the danger of eutrophication. In the domain of adsorption, high specific area hydrophilic LDHs with an increased anionic exchanging capability are commonly utilized.
Because of the synergy, combining phosphate and LDHs may not only increase phosphate stability but also significantly enhance LDH adsorptive efficacy for U(VI). Furthermore, they have a higher adsorptive potential and a cheaper cost than certain polymers such as Polypyrrole, Polydopamine.
What was Done in the Study?
In this study, monodispersed hollowed Fe3O4 nanoscale spherical structures were covered with phosphate-modified layered double hydroxides (phos-LDH) to create h-Fe3O4@phos-LDH, a unique core-shell oriented nanoscale composite.
The adsorptive efficiency of the composite on U(VI) was thoroughly investigated under various ambient variables (ionic strength, acidity, heat, and adsorptive period).
To conclude, a magnetized h-Fe3O4@phos-LDH nanoscale composite was effectively produced and used to remove uranium (VI) from water bodies and soil in this study.
It was discovered via the experiments that the peak adsorptive potential is greater than that of several earlier documented substances. According to the adsorptive isotherms and thermochemical analyses, this removal process is a single layer adsorption with an endothermic response at the surface.
The mechanism research revealed that the procedure of U(VI) adsorbed by h-Fe3O4@phos-LDH is inner-sphere surface complexation, which is consistent with previous findings. Additionally, the straightforward electromagnetic separating technique may be employed to quickly and efficiently remove h-Fe3O4@phos-LDH from water and soil.
The team created a simple and viable technique for extracting U(VI) from soil and water, which has a wide range of potential applications in the field of environmental science.
Zhang, J., Wang, D., Cao, R., & Li, J. (2022). Hollow Fe3O4 nanospheres covered by phosphate-modified layered double hydroxides for the removal of uranium (VI) from water and soil. Separation and Purification Technology. Available at: https://www.sciencedirect.com/science/article/pii/S1383586622002489?via%3Dihub