Selective regulation of peroxydisulfate-to-hydroxyl radical for efficient in-situ chemical oxidation over Fe-based metal-organic frameworks under visible light

Selective regulation of peroxydisulfate (PDS) activation-to-hydroxyl radical (OH) production (PDS-to-OH) is important for in situ chemical oxidation. However, the regulation mechanisms still lack reasonable explorations. Herein, a novel system involving the selective regulation of PDS-to-OH was investigated using Fe-based metal-organic frameworks (MOF; MIL-100(Fe)) under visible light irradiation. Spectroscopic characterizations and controlled experiments indicated that the PDS chemically linked between coordinatively unsaturated metal sites (CUSs) and coordinated H2O in MIL-100(Fe) plays critical role in regulating the PDS-to-OH transformation. Consequently, the constructed PDS/MIL-100(Fe) system showed improved performance not only in the organic degradation rate but also in PDS utilization efficiency compared with that of the traditional sulfate radical (SO4 center dot(-))mediated PDS/MIL-68(Fe) system. This work provides new insights into the regulation of PDS activation to center dot OH generation over heterogeneous catalysis. Moreover, considering the diverse compositions and structures of MOFs, this work also demon-strates their feasibility as efficient light-induced materials for in situ chemical oxidation. (C) 2021 Elsevier Inc. All rights reserved.