Efficient peroxydisulfate activation with γ-Al2O3-C-MIL-100(Fe) framework for sulfamethazine degradation: Enhanced oxidant utilization and reduced metal leaching

Low degradation efficiency and significant transition metal leaching are two challenges in persulfate activation systems based on metal-organic frameworks (MOFs) for organic pollutant degradation. Here, the challenges were solved by designing and synthesizing a micron-sized core-shell material, γ-Al 2 O 3 -C-MIL-100(Fe) (γACM), by coating the γ-Al 2 O 3 core with carbon (γ-Al 2 O 3 -C) and futher modifying with MIL-100(Fe). Testing γACM with sulfamethazine (SMZ) demonstrated its outstanding peroxydisulfate (PDS) activation, achieving 92.5 % SMZ removal within 20 min at a low oxidant/pollutant ratio. Fe leaching from γACM was effectively inhibited, with only 3.59 % Fe lost after three recycles. The system showed adaptability across a wide pH range, and usability in sewage effluent, indicating promise for practical application. The hydrophobicity of γ-Al 2 O 3 -C, the coordinatively unsaturated sites in MIL-100(Fe), and the strong bounding of MIL-100(Fe) on γ-Al 2 O 3 -C ensured the effective SMZ gather, PDS activation, and Fe stability respectively, which led to the excellent performances of γACM.