ZnO/AAO photocatalytic membranes for efficient water disinfection: Synthesis, characterization and antibacterial assay

Autor: Ali Akbar, Syed Muzamil Ali Bokhari, Izabela Stroe, Ajab Khan Kasi, Bibi Najma, Jafar Khan Kasi
Rok vydání: 2018
Předmět:
Zdroj: Applied Surface Science. 448:104-114
ISSN: 0169-4332
DOI: 10.1016/j.apsusc.2018.04.063
Popis: Novel type of ZnO/AAO photocatalytic membranes were fabricated by growing highly dense and porous network of ZnO nanosheets on nanoporous anodic aluminum oxide (AAO) using the facile hydrothermal approach. The structural properties of the membranes were investigated by field emission gun scanning electron microscopy (FEG-SEM) and X-ray diffraction spectroscopy (XRD). The ZnO nanosheet networks were found polycrystalline, showing mainly (100) and (002) ZnO reflections. The XRD results suggested that the ZnO-AAO interface promotes lattice disorder mainly along the polar-axis while the nonpolar plane remains less defective. The energy dispersive X-ray spectrometry (EDX) confirmed the formation of pure ZnO. In addition, Fourier transform infrared spectroscopy (FTIR) indicated an intense absorption band in the range of 661–780 cm−1 for stretching vibrations of Zn–O bond and also specified the presence of intrinsic crystal defects. The diffuse reflectance spectroscopy (DRS) revealed an optical absorption edge of 401 nm and a band gap of 3.09 eV for grown ZnO nanosheet mesh. Moreover, the DRS studies also substantiated the existence of crystal defects by recognizing a red shift in the band gap, and a trail of low energy absorptions in the reflectance spectrum in the range of 400–800 nm. Due to the corrugated surface morphology and hierarchical porosity of ZnO scaffolds on porous AAO substrates, the membranes possess a great deal of catalytic surface and demonstrated a strong antibacterial activity against water-borne bacteria Escherichia coli (E. coli) under dark and UV light conditions. Our results showed that fabricated ZnO/AAO membranes have great potency for photocatalytic disinfection of contaminated water on account of their large catalytic surface and inherent porosity which can facilitate the mass transfer and diffusion of oxygen species and Zn+2 ions during the disinfection process. This morphology-function relationship is highly effective for designing cost effective, efficient, environment-friendly, and self-antifouling photocatalytic disinfectants.
Databáze: OpenAIRE
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