Microwave-assisted solvothermal synthesis of cube-shaped MOF-COF composites for copper detection and capture

A novel metal organic framework-covalent organic framework (IRMOF3-TzDa) composite was prepared by microwave-assisted solvothermal methods. The designed IRMOF3-TzDa was integrated with dual function of copper ion detection and removal, and characterized by FTIR, XRD, SEM, TEM and XPS et al. The adsorption capacity of Cu2+ by IRMOF3-TzDa was 86 mg g−1 by Langmuir isotherm model fitting. In a mixed metal ions solution, IRMOF3-TzDa demonstrated high adsorption selectivity to Cu2+. The strong affinity between IRMOF3-TzDa and Cu2+ and the rapid transfer of the π electrons of the material to the lowest unoccupied molecular orbital of Cu2+ provided the chance for Cu2+ fluorescence sensing by IRMOF3-TzDa. A linear range of 10–500 μM was obtained, with a limit of detection of 2.2 μM (n = 11) and a precision of 3.3% (50 μM, n = 9), respectively. Water samples were analyzed by the detection platform, with satisfactory recoveries of 94% to 107%. Benefiting from the high density of adsorption groups and excellent fluorescence properties, the facile synthetic MOF-COF composite provided an alternative material for copper ion removal and detection.