Synthesis of TiO2 Composite Nanofibers Doped with Copper Oxide Nanoparticles through Electrospinning and Their Application in Photocatalytic Degradation of Pharmaceutical Wastewaters

Abstract

Hypothesis: The photocatalysis process can be an appropriate alternative for traditional methods of pharmaceutical wastewater treatment because of its complete mineralization of pollutants and an environmentally friendly method. In challenging the drawbacks of photocatalytic TiO2-based nanoparticles such as aggregation and separation, photocatalytic TiO2-CuO nanofibers were produced through electrospinning technique and their photocatalytic capability was evaluated.Methods: A TiO2-CuO nanostructured composite was synthesized by loading CuO nanoparticles on the electrospun TiO2 nanofibers through solid state dispersion method and characterized by X-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), BET (Brunauer-Emmett-Teller), differential reflectance spectroscopy (DRS) and photoluminescence (PL) analysis. By studying and exploring the photocatalysis of TiO2-CuO composite nanofibers in pharmaceutical wastewaters treatment, the synthesized sample was tested in the photodegradation of tetracycline as the most widely used antibiotics. Findings: The XRD, FE-SEM and EDX results confirmed the synthesis of composite nanofibers. The XRD pattern showed the crystal structure of TiO2 was mainly in the form of anatase. FE-SEM images demonstrated the relatively uniform dispersion of CuO nanoparticles in nanofibers. The results of optical spectroscopy analysis revealed a lower band gap of the synthesized nanofibers compared to TiO2-free nanofibers and nanoparticles; and relatively low electron-hole recombination which are the main characteristics of an effective photocatalyst. The BET analysis depicted a specific surface area of 8.5 m2/g and a mesoporous structure of the synthesized product. Finally, the photocatalytic activity of composite nanofibers was investigated in the photodegradation of tetracycline at various pH levels of wastewater. The TiO2-CuO composite nanofibers exhibited tetracycline degradation efficiency of 71% at neutral pH which is in accordance with the obtained data on sample characterization. These observations and findings together with the comparison of the photocatalytic performance of the synthesized sample compared with literature review verify the photocatalytic characteristics and the capability of TiO2-CuO composite nanofiber in pharmaceutical wastewaters treatment.

Keywords

• tio2 nanofibers
• copper oxide nanoparticles
• electrospinning method
• photocatalytic treatment
• tetracycline