Abstract
Kaolinite nanotubes were synthesized by a simple scrolling process and decorated by ZnO nanoparticles as a novel nanocomposite (ZnO/KNTs). The synthetic ZnO/KNTs composite was characterized as an effective photocatalyst in the oxidation of levofloxacin pharmaceutical residuals in the water resources. The composite displays a surface area of 95.4 m2/g, average pore diameter of 5.8 nm, and bandgap energy of 2.12 eV. It is of high catalytic activity in the oxidation of levofloxacin in the presence of visible light source. The complete oxidation for 10 mg/L of levofloxacin was recognized after 55 min, 45 min, and 30 min with applying 30 mg, 40 mg, and 50 mg of ZnO/KNTs as catalyst dosage, respectively. Additionally, it achieved complete oxidation for 20 mg/L and 30 mg/L of levofloxacin after 45 min and 75 min, respectively using 50 mg as catalyst dosage. The degradation efficiency was confirmed by detecting the residual TOC after the treatment tests and the formed intermediate compounds were identified to suggest the degradation pathways. In addition to the oxidation pathway, the mechanism was evaluated based on the active trapping tests that proved the dominance of hydroxyl radicals as the essential active species. Finally, the ZnO/KNTs composite is of promising recyclability properties and achieved better results than several studied photocatalysts in literature.
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•ZnO/KNTs photocatalyst was synthesized for effective oxidation of levofloxacin.•The catalyst is of promising surface area (95 m2/g) and bandgap energy (2.12 eV).•99% of levofloxacin (10 mg/L) was oxidized after 30 min using 50 mg of ZnO/KNTs.•The catalyst is of high recyclability value and reused effectively for five runs.•The hydroxyl radicals were detected as the main oxidizing species in the system.