Phosphate group functionalized magnetic metal–organic framework nanocomposite for highly efficient removal of U(VI) from aqueous solution

Abstract

The phosphate group functionalized metal-organic frameworks (MOFs) as the adsorbent for removal of U(VI) from aqueous solution still suffer from low adsorption efficiency, due to the low grafting rate of groups into the skeleton structure. Herein, a novel phosphate group functionalized metal–organic framework nanoparticles (denoted as Fe3O4@SiO2@UiO-66-TPP NPs) designed and prepared by the chelation between Zr and phytic acid, showing fast adsorption rate and outstanding selectivity in aqueous media including 10 coexisting ions. The Fe3O4@SiO2@UiO-66-TPP was properly characterized by TEM, FT-IR, BET, VSM and Zeta potential measurement. The removal performance of Fe3O4@SiO2@UiO-66-TPP for U(VI) was investigated systematically using batch experiments under different conditions, including solution pH, incubation time, temperature and initial U(VI) concentration. The adsorption kinetics, isotherm, selectivity studies revealed that Fe3O4@SiO2@UiO-66-TPP NPs possess fast adsorption rates (approximately 15 min to reach equilibrium), high adsorption capacities (307.8 mg/g) and outstanding selectivity (Su = 94.4%) towards U(VI), which in terms of performance are much better than most of the other magnetic adsorbents. Furthermore, the adsorbent could be reused for U(VI) removal without obvious loss of adsorption capacity after five consecutive cycles. The research work provides a novel strategy to assemble phosphate group-functionalized MOFs.

Phosphorus-Modified Metal-Organic Frameworks for the Effective Removal of Thorium from Aqueous Solutions

“…Since phytic acid is rich in phosphate groups, it can easily chelate with metal ions in aqueous media through electrostatic adsorption and surface complexation interactions 32 . On one hand, phytic acid has been demonstrated as an effective functionalizing moiety in experimental study of uranium adsorption 33 . On the other hand, thorium in the natural environment typically exists in the tetravalent state.…”

Synthesis of core–shell magnetic metal organic framework composite for the efficient removal of uranium(vi)

“…[42][43][44] For example, coating the surface of Fe 3 O 4 with SiO 2 can prevent the agglomeration and oxidation of Fe 3 O 4 , and is also conducive to further modification with functional groups. [45][46][47][48] Fe 3 O 4 /SiO 2 core-shell composites could rapidly adsorb uranium(VI), but their adsorption capacity was low. 49 Thus, improving the adsorption performance of materials for uranium(VI) is very important and a hot research topic.…”