In-situ confined growth of defective MIL-100(Fe) in macroporous polyacrylate spherical substrate at room temperature for high-efficient toluene removal

The hazard caused by toluene has attracted worldwide attention, and it is of practical significance to study the efficient adsorption of toluene for environmental governance. In this work, a hierarchical metal–organic framework (MOF), MIL-100(Fe), was crystallized on the surface of a macroporous polyacrylate (PAA) spherical substrate at room temperature through an in-situ confinement growth strategy to form MIL-100(Fe)@PAA composite. By decreasing the nucleation energy barrier, the average size of MIL-100(Fe) crystals was reduced from 400 nm to 55 nm and defects as adsorption sites for toluene were able to install in the crystal lattices. Therefore, the composite provided excellent static and dynamic adsorption properties for toluene, much better than the pristine MIL-100(Fe). The potential mechanism for crystal defects to significantly improve the adsorption performance was subsequently explored through kinetic fitting and density functional theory (DFT) calculation. All results indicated that the innovative MIL-100(Fe)@PAA prepared using defect engineering and effective molding technology was potent in both toluene removal and regeneration, which was expected to provide a new avenue for the facile synthesis of molded MOF composites.