Facile strategy to separate uranium (VI) using glued Amidoxime-functionalized composite beads synthesized from aqueous solution

• 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.