MOF (M=Zr, Zn, Co)@COFs hybrid composite as a potential adsorbent for UO22+ and Methylene blue (MB) from solutions.

Using the in situ solvothermal method, zirconium, zinc, and cobalt [email protected] hybrid composites are synthesized and employed to remove uranium (UO22+) and Methylene blue (MB). IR spectra, powdered X-ray diffraction (PXRD), X-ray Photoelectron Spectroscopy (XPS), and scanning electron microscopy (SEM)-energy dispersive spectroscopy (EDS) all confirmed the formation of [email protected] hybrid composites. Using the Brunauer-Emmett-Teller (BET) method, the surface area was calculated to be 748.215 m2/g, 898.376 m2/g, and 551.848 m2/g for [email protected], 2, and 3, respectively. The maximum adsorption capacity of UO22+ by [email protected] composites in aqueous solution at pH 8.2 is 399.6 mg/g for [email protected], 538.31 mg/g for [email protected], and 424.54 mg/g for [email protected] In contrast, methylene blue (MB) was recovered only by [email protected] with 142.68 mg/g at pH-4, substantiated by the well-fitted Langmuir adsorption isotherm. UO22+ and MB pseudo-second-order kinetics indicate that the adsorption process is driven by electrostatic interaction and surface complexation between the adsorbent and the adsorbate. In addition, the adsorption of MB and UO22+ utilizing the fixed bed column technique was investigated by studying the well-fit Thomas and Yoon-Nelson models. By examining the XPS, FTIR, and SEM-EDS (Mapping) data obtained before and after the adsorption of UO22+, a potential mechanism of electrostatic interactions and surface complexation between the adsorbate and adsorbents was proposed. Additionally, [email protected] composites were tested in the simulated seawater, and UO22+ sorption was successfully studied. The regeneration process shows that adsorbent was successfully applied for up to 8 cycles in the recovery of UO22+.