Amino-functionalized iron-based MOFs for Rhodamine B degradation in heterogeneous photo-Fenton system

Amino-functionalized iron-based MOFs were successfully synthesized and used for the photo-Fenton-catalyzed degradation of Rhodamine B (RhB). The degradation efficiency of NH2-MIL-53(Fe) towards RhB (95.0%) exceeded that of NH2-MIL-88B(Fe) (87.0%) and NH2-MIL-101(Fe) (88.0%), which might be mainly because that NH2-MIL-53(Fe) had the most suitable specific surface area and pore volume, and the best light absorption properties. Additionally, NH2-MIL-53(Fe) exhibited higher degradation efficiency than MIL-53(Fe) (84.0%), possibly owing to the incorporation of amino functional groups that inhibited the recombination of photogenerated electron-hole pairs and enhanced visible light responsiveness. Remarkably, NH2-MIL-53(Fe) had a good degradation effect on RhB in a wide range of pH (3.0-7.0), and the degradation rate was still as high as 90.0% after 5 consecutive degradation experiments. The degradation process was predominantly influenced by the involvement of & sdot;OH and 1O2, as evidenced by the outcomes of free radical capture experiments. Possible degradation pathways of RhB were proposed by mass spectrometry.