Removal of Co(II) from aqueous solution with Zr-based magnetic metal-organic framework composite

The highly specific enrichment of Co-60 from radioactive wastewater is the precondition of reducing radioactive contamination and ensuring the safety of watery environments. Herein, a novel glucose functionalized magnetic zirconium-based metal-organic framework (MOF) composite (Fe3O4@SiO2@UiO-66-Glu) was successfully prepared and utilized for the removal of Co(II) from aqueous solution. The effect of pH, contact time, initial Co(II) concentration, temperature and reusability had been explored. Results indicated that Co(II) adsorption reached equilibrium after eight hours, the maximum adsorption capacity of Fe3O4@SiO2@UiO-66-Glu for Co(II) was 178.6 mg g at 288 K, 222.2 mg g(-1) at 298 K, and 270.3 mg g(-1) at 308 K. Besides, data obtained were fitted to Langmuir isotherm model, while the thermodynamic and kinetic parameters also showed that the adsorption process was spontaneous and endothermic by pseudo-second-order chemisorption. In addition, the synthesized composite displayed excellent regeneration availability in the recycle applications. As far as we know, this is the first time that magnetic MOFs are used exclusively for the separation of cobalt ions, which have the great potential to uptake Co-60 from environmental wastewater.