Porous boron nitride-loaded ZIF-67 composites for highly efficient removal of uranium (VI) from aqueous solution

The discharge of uranium-containing wastewater from nuclear fuel production poses severe threats to human health and environmental security due to the high mobility, solubility, and radiotoxicity of hexavalent uranium (U(VI)). However, developing an adsorbent that simultaneously achieves high adsorption capacity, fast kinetics, strong selectivity and good recyclability remains a major challenge. In this paper, porous boron nitride-loaded ZIF-67 composites (BN@ZIF-67-X) were synthesized by a simple in situ growth method and used for the removal of U(VI) from aqueous solutions. The results showed that BN@ZIF-67 exhibited excellent adsorption properties for U(VI) than pure p-BN and ZIF-67. It also demonstrated acceptable cyclic regeneration properties. In addition, the adsorption of U(VI) by BN@ZIF-67-2 achieved equilibrium within 60 min, the adsorption kinetics were well-described by the pseudo-second-order model, the isothermal model conformed to the Langmuir isothermal model, and the adsorption was an endothermic monolayer chemisorption process. The maximum adsorption capacity of U(VI) by BN@ZIF-67-2 was calculated to be 550.306 mg g −1 . Moreover, the adsorption of BN@ZIF-67-2 exhibited excellent selectivity in the adsorption of U(VI), which was dominated by surface complexation. In conclusion, BN@ZIF-67 is a promising adsorbent for the adsorption of U(VI) from aqueous solution.