Embedded ZnO nanorod array/TiO2/GO coated optical fiber in a photocatalytic microreactor for Cefixime degradation: Diffused or focused light sources effect

Abstract

A new high-efficiency continuous photocatalytic system composed of a microreactor and an optical fiber coated with a ZnO nanorod array/TiO2/GO with a retention time of 4–7 min was introduced. Using a new step-by-step chemical bath deposition method, a ZnO nanorod array coated with TiO2 and GO was grown on the surface of an optical fiber with different mass ratios. The coated photocatalytic layer was characterized using XRD, XPS, Raman spectra, UV-drs, TEM, and SEM. The photocatalytic degradation efficiency of Cefixime (CEF) in the microreactor was studied under irradiation from two diffusing and focusing light sources to determine the effect of light radiation type on the efficiency. ZnO nanorods/TiO2 coated optical fiber (Ti/Zn weight ratio = 0.37) and GO deposition during the growth of ZnO nanorods demonstrated the highest degradation efficiency. The operational and geometrical parameters were optimized as fiber length = 15 cm, fiber diameter = 500 µm, CEF concentration = 10 ppm, and pH = 4.8. The removal efficiency under these conditions was approximately 67 % with a diffused light source and 80.1 % with a focused light source. The coated photocatalytic composite showed high stability to the liquid flow after 1200 min of continuous operation, indicating the ZnO nanorods/TiO2/GO coating method's success.