Succinamic Acid Grafted Nanosilica for the Preconcentration of U(VI) from Aqueous Solution

Enhanced Versatility in Thorium Removal: Mesoporous Silica-Coated Magnetic Nanoparticles Functionalized by Phenanthroline Diamide as a Selective Adsorbent

In order to promote the sustainable development of nuclear energy through thorium (Th(IV)) recycling, we synthesized SiO2-coated magnetic functional nanocomposites (SiO2@Fe3O4) that were modified with 2,9-diamide-1,10-phenanthroline (DAPhen) to serve as an adsorbent for Th(IV) removal. SiO2@Fe3O4-DAPhen showed effective Th(IV) adsorption in both weakly and strongly acidic solutions. Owing to its porous structure that facilitated rapid adsorption kinetics, equilibrium was achieved within 5 and 0.5 min at pH 3 and 1 mol L-1 HNO3, respectively. In weakly acidic solutions, Th(IV) primarily formed chemical coordination bonds with DAPhen groups, while in strongly acidic solutions, the dominant interaction was electrostatic attraction. Density functional theory (DFT) calculations indicated that electrostatic attraction was weaker compared to chemical coordination, resulting in reduced diffusion resistance and consequently faster adsorption rates in strongly acidic solutions. Furthermore, SiO2@Fe3O4-DAPhen exhibited a high adsorption capacity for Th(IV); it removed Th(IV) through chelation and electrostatic attraction at pH 3 and 1 mol L-1 HNO3, with maximum adsorption capacities of 833.3 and 1465.7 mg g-1, respectively. SiO2@Fe3O4-DAPhen also demonstrated excellent tolerance to salinity, adsorption selectivity, and radiation resistance, thereby highlighting its practical potential for Th(IV) removal in diverse contaminated water sources. Hence, SiO2@Fe3O4-DAPhen represents a promising choice for the rapid and efficient removal of Th(IV).

An Efficient Uranium Adsorption Magnetic Platform Based on Amidoxime-Functionalized Flower-like Fe3O4@TiO2 Core-Shell Microspheres

Efficient removal of uranium (U) from aqueous solutions is crucial for ecological safety. Functionalized magnetic nanoparticles provide a promising strategy for radionuclide recovery and separation. However, designing and synthesizing magnetic adsorbents with high sorption capacity and selectivity, accompanied by excellent stability and reusability, remain a challenge. In this work, novel amidoxime-functionalized flower-like magnetic Fe₃O₄@TiO₂ core-shell microspheres are designed and synthesized to efficiently remove U(VI) from aqueous solutions and actual seawater. The magnetic Fe₃O₄ core facilitates easy separation by an external magnetic field, and flower-like TiO₂ nanosheets provide abundant specific surface areas and functionalization sites. The grafted amidoxime (AO) groups could function as a claw for catching uranium. The maximum adsorption capacity on U(VI) of the designed nanospheres reaches 313.6 mg·g^-1 at pH 6.0, and the adsorption efficiency is maintained at 97% after 10 cycles. In addition, the excellent selectivity of the magnetic recyclable AO-functioning Fe₃O₄@TiO₂ microspheres endows the potential of uranium extraction from seawater. The designed material provides an effective and applicable diagram for radioactive element elimination and enrichment.

Removal of U(VI) from aqueous and polluted water solutions using magnetic Arachis hypogaea leaves powder impregnated into chitosan macromolecule

In this study m-AHLPICS (magnetic Arachis hypogaea leaves powder impregnated into chitosan) was prepared and utilized as an adsorbent to remove U(VI) from aqueous and real polluted wastewater samples. m-AHLPICS was characterized by using the BET, XRD, FTIR, SEM with elemental mapping and magnetization measurements. Different experimental effects such as pH, dose, contact time, and temperature were considered broadly. Chitosan modified magnetic leaf powder (m-AHLPICS) exhibits an excellent adsorption capacity (232.4 ± 5.59 mg/g) towards U(VI) ions at pH 5. Different kinetic models such as pseudo-first-order, and pseudo-second-order models were used to know the kinetic data. Langmuir, Freundlich and D-R isotherms were implemented to know the adsorption behavior. Isothermal information fitted well with Langmuir isotherm. Kinetic data followed by the pseudo-second-order kinetics (with high R² values, i.e., 0.9954, 0.9985 and 0.9971) and the thermodynamic data demonstrate that U(VI) removal using m-AHLPICS was feasible, and endothermic in nature.

The preparation of organophosphorus ligand-modified SBA-15 for effective adsorption of Congo red and Reactive red 2

P,P-bis (2-oxooxazolidin-3-yl)-N-(3-(triethoxysilyl)propyl)phosphinic amide (APTES-BOP)-modified SBA-15 (SBA-15-BOP) was prepared by a post-synthesis grafting method for the removal of anionic azo dyes from aqueous solutions. The properties of the prepared adsorbent were characterized by PXRD, FT-IR, SEM, TEM, nitrogen sorption, and elemental analysis. Adsorption equilibrium and adsorption kinetic studies demonstrated that the experimental data fitted well with the Langmuir isotherm model and pseudo-second-order model. According to Langmuir fitting, SBA-15-BOP showed high adsorption capacity for CR and RR2 dyes, with the maximum adsorption capacities of 518.1 mg g⁻¹ and 253.8 mg g⁻¹, respectively. The thermodynamic study indicated that the adsorption processes of CR and RR2 dyes on SBA-15-BOP were spontaneous and exothermal. The prepared SBA-15-BOP can be a promising adsorbent for the removal of anionic dyes from aqueous solutions.

P,P-bis (2-oxooxazolidin-3-yl)-N-(3-(triethoxysilyl)propyl)phosphinic amide (APTES-BOP)-modified SBA-15 (SBA-15-BOP) was prepared by a post-synthesis grafting method for the removal of anionic azo dyes from aqueous solutions.

Rationally designed core-shell and yolk-shell magnetic titanate nanosheets for efficient U(VI) adsorption performance

The hierarchical core-shell and yolk-shell magnetic titanate nanosheets (Fe₃O₄@TNS) were successfully synthesized by employing magnetic nanoparticles (NPs) as interior core and intercrossed titanate nanostructures (NSs) as exterior shell. The as-prepared magnetic Fe₃O₄@TNS nanosheets had high specific areas (114.9 m² g^-1 for core-shell Fe₃O₄@TNS and 130.1 m² g^-1 for yolk-shell Fe₃O₄@TNS). Taking advantage of the unique multilayer structure, the nanosheets were suitable for eliminating U(VI) from polluted water environment. The sorption was strongly affected by pH values and weakly influenced by ionic strength, suggesting that the sorption of U(VI) on Fe₃O₄@TNS was mainly dominated by ion exchange and outer-sphere surface complexion. The maximum sorption capacities (Q_max) calculated from the Langmuir model were 68.59, 121.36 and 264.55 mg g^-1 for core-shell Fe₃O₄@TNS and 82.85, 173.01 and 283.29 mg g^-1 for yolk-shell Fe₃O₄@TNS, at 298 K, 313 K and 328 K, respectively. Thermodynamic parameters (ΔH⁰, ΔS⁰ and ΔG⁰) demonstrated that the sorption process was endothermic and spontaneous. Based on X-ray photoelectron spectroscopy (XPS) analyses, the sorption mechanism was confirmed to be cation-exchange between interlayered Na⁺ and UO₂²⁺. The yolk-shell Fe₃O₄@TNS had more extraordinary sorption efficiency than core-shell Fe₃O₄@TNS since the yolk-shell structure provided internal void space inside the titanate shell to accommodate more exchangeable active sites. The flexible recollection and high efficient sorption capacity made core-shell and yolk-shell Fe₃O₄@TNS nanosheets promising materials to eliminate U(VI) or other actinides in wastewater cleanup applications.