Constructing cactus-like mixed dimensional MOF@MOF as sorbent for extraction of bisphenols from environmental water

Metal-organic frameworks (MOFs) received considerable attention to adsorption and removal of various environmental pollutants because of some inherent advantages. However, it is challenging but meaningful to design and fabricate hierarchical mixed-dimensional MOFs with synergistic effects to enhance the performance for removal and preconcentration of environmental pollutants. Herein, a new hierarchical two-dimensional (2D)-three-dimensional (3D) mixed-dimensional cactus‐like MOF@MOF hybrid material (PCN-134@Zr-BTB) was prepared by in-situ growth of 2D MOF nanosheets (Zr-BTB) on the surface of 3D MOF (PCN-134). The PCN-134@Zr-BTB composites combine the advantages of 2D and 3D MOFs with extensive mesoporous structures and large surface area for effective removal and enrichment of bisphenols (BPs). In comparison with pristine PCN-134 and Zr-BTB materials, the PCN-134@Zr-BTB hybrid material presented excellent adsorption performance for BPs. The adsorption isotherms are consistent with the Langmuir model, and the maximum adsorption capacity of four bisphenols (BPs) ranged from 135.1 mg/g to 628.9 mg/g. The adsorption kinetics are in accordance with the pseudo-second-order model. The recoveries ranged from 72.8% to 108%. The limits of detection were calculated at 0.02–0.03 ng/mL. The enrichment factors were calculated in the range of 310–374. According to FT-IR and XPS analysis, the main adsorption mechanisms are hydrogen bonding and π-π stacking. Nevertheless, this work provides a new and convenient strategy for the preparation of new hierarchical mixed-dimensional MOF@MOF (PCN-134@Zr-BTB) hybrid material for extraction and enrichment of BPs from aqueous matrix.