Search

[Display omitted] • The nitrile-immobilized composite was first synthesized via a one-pot method in oil/water phase. • The uranium-loaded sorbent can be easily separated from liquid under the action of an external magnetic field. • The sorption can reach dynamic equilibrium within 90 min. • The sorption process is spontaneous and endothermic via thermodynamic study. • XPS analysis revealed three possibilities for the sorption mechanism of uranium on MMS-AO. The use of inexpensive and biocompatible sorbents for effective removal of uranium from water environment is still an open challenge for many researchers. Herein, the magnetic amidoxime-functionalized mesoporous silica (MMS-AO) has been prepared by a combination of soft template method and co-condensation method in weak alkali oil/water phase. A feature of MMS-AO is core–shell configuration with Fe 3 O 4 service as core, which makes the material easy to be recovered by an external magnetic field after sorption. Various characterization techniques of SEM, TEM, N 2 sorption–desorption, FT-IR, TGA, Zeta potential and VSM were applied to evaluate MMS-AO. Batch sorption experiments confirmed that there were some good behavior to U(VI) removal on MMS-AO from aqueous including sorption capacity, selectivity and reusability. The experimental data fitted well to Langmuir isotherm model and the pseudo-second-order kinetic model. The maximum sorption amount at 298 K and pH 5.50 was 236.70 mg·g−1 and the dynamic equilibrium can be reached in 90 min. The sorption process is spontaneous and endothermic via thermodynamic study. The analysis of XPS provided three insights on mechanism based on the chelation of U(VI) with amidoxime groups. [ABSTRACT FROM AUTHOR]

[Display omitted] • The amidoxime group was successfully anchored in mesoporous silicon by co-condensation method. • Mesoporous silica powder was gluded into composite beads by biological glue to achieve rapid recovery. • Herein, three mechanisms can explain the adsorption behavior of U(VI) by Al/MS-AO. Uranium is both an important resource and an environmental hazard. It is vital to separate/enrich uranium from liquid for energy production as well as for environmental protection. Herein, the amidoxime-functionalized mesoporous silica/calcium alginates (Al/MS-AO) were synthesized by co-condensation and post-gluing process. The morphology and the characteristics of the Al/MS-AO were studied by using Scanning electron microscope (SEM), energy dispersive spectrometer (EDS), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), N 2 adsorption–desorption and X-ray photoelectron spectroscopy (XPS). These analyses have also revealed the in-depth information of the materials including function groups, structure, and Uranium adsorption mechanism. Batch experiments were conducted, and the results suggest that the adsorption of uranium by Al/MS-AO is a spontaneous and endothermic process. This process can be described with the combination of a pseudo second order kinetic model and a Langmuir isotherm model. The maximum adsorption capacity achieved is 328.68 mg·g−1. Three possible adsorption mechanisms are proposed, which involve the chemical chelation of the N and O atoms of amidoxime. [ABSTRACT FROM AUTHOR]