Preparation of magnetic Fe3O4/g-C3N4 nanosheets immobilized with hierarchal Bi2WO6 for boosted photocatalytic reaction towards antibiotics in aqueous solution: S-type charge migration route

The search for visible-light-response, stable, and recyclable photocatalysts for pollutant degradation is still a huge challenge. In this respect, a novel magnetic Bi2WO6/Fe3O4/g-C3N4 nano-hybrid (BWO/FO/GCN) was designed and constructed via three steps for the mineralization of antibiotics under visible and sunlight irradiation. Strong interfacial contact was achieved by anchoring hierarchical Bi2WO6 (BWO) and Fe3O4 (FO) nanoparticles onto g-C3N4 nanosheets (GCN), obtaining an S-type charge transfer system. The optimized BWO/FO/GCN heterojunction proved favorable disadvantages, such as highly solar-light utilization, outstanding photoredox capacity, faster spatial charge disintegration, easily magnetic separation, inexpensive, and environmentally friendly. Besides, the S-type heterojunction reflected an exceptional catalytic degradation efficiency of 84.5 % and 61.4 % in 50 min against the levofloxacin (LEV) antibiotic under visible and sunlight irradiation, respectively. Moreover, the optimized BWO/FO/GCN manifested an upgraded degradation constant that was greater than pure g-C3N4 and Bi2WO6 by 4.73 and 3.78, respectively. On the other hand, the trapping studies declared that (OH)-O-center dot and O-center dot(2)- are major reactive oxidants in photoreaction. The cyclic outcomes demonstrated the remarkable durability of BWO/FO/GCN in five LEV degradation cycles with a practical magnetic recycling process. Finally, this work encourages the construction of another type of S-type nanocomposites reinforced by magnetic characteristics for practical applications.