Highly dispersed Ag and g-C3N4 quantum dots co-decorated 3D hierarchical Fe3O4 hollow microspheres for solar-light-driven pharmaceutical pollutants degradation in natural water matrix

The efficient removal of pharmaceutical pollutants presents a great challenge for the conventional sewage treatment system. Herein, we document the nanosheets assembled 3D hierarchical Fe₃O₄ hollow microspheres co-modified by Ag and g-C₃N₄ quantum dots (Ag/CNQDs@Fe₃O₄) for efficient degradation of two classic anticancer drugs, i.e., capecitabine (CAP) and 5-fluorouracil (5-FLU) under visible light in 1 h. Benefiting from the unique hierarchically hollow structure, the intrinsic strengths of each component and their interactions, synergistic reinforcing mechanism is constructed, furnishing more accessible reactive places, promoting the diffusion of pollutants/oxidants, improving charge separation ability, and raising light utilization rate. Consequently, Ag/CNQDs@Fe₃O₄ can not only show superior photocatalytic properties, but also greatly boost PMS activation to yield sufficient oxidative radicals. More notably, the studied system also features excellent stability and strong tolerance to real water samples, and maintains appreciable performance even under natural sunlight illumination. The predominant active species, possible ADs decomposition pathways, and underlying reaction mechanism for the Ag/CNQDs@Fe₃O₄/PMS/vis system are thoroughly explored. This work presents significant advancement in enabling an integrated technology of PMS and photocatalysis to realize its great potential in environment restoration.