Facile synthesis of recyclable 3D gelatin aerogel decorated with MIL-88B(Fe) for activation peroxydisulfate degradation of norfloxacin.

The application of traditional powder catalysts is limited by particle agglomeration and difficult recovery. In this work, a three-dimensional porous aerogel catalyst for organic pollutants degradation in water by activating peroxydisulfate (PDS) was successfully synthesized, which was obtained via directly mixing of MIL-88B(Fe) with sol precursors followed by vacuum freeze-drying and low-temperature calcination. MIL-88B(Fe)/gelatin aerogel-150/PDS (MGA-150/PDS) system displayed satisfactory norfloxacin (NOR) degradation performance, which could remove 98.7% of NOR in 90 min. Its reaction rate constant was 23.2 times higher than the gelatin aerogel/PDS (GA/PDS) system. In addition, Electron paramagnetic resonance (EPR) results and radical trapping experiments revealed both radicals (SO, •OH) and non-radical (O) pathways had participated in NOR degradation, of which •OH was dominant. Possible degradation pathways were proposed. Moreover, the high degradation efficiency of NOR by MGA-150 composites could still be reached more than 90.0% even after 10 cycles, and the morphology and chemical structure of MGA-150 composites exhibited no significant changes, indicating the arrestive stability of aerogel composites. This progress not only proposed an effective catalyst for PDS activation, but also expanded views for the design and development of 3D functional materials.