Energy Efficient UV-LED Source and TiO2 Nanotube Array-Based Reactor for Photocatalytic Application

The present study focuses on the development and feasibility of ultraviolet light emitting diode (UV-LED) source and TiO2 nanotube array (TNA)-based photocatalytic reactor for Congo red (CR) dye degradation. Highly ordered TNA was synthesized by the anodization method. The synthesized highly ordered TNA was characterized by X- ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscope (AFM), and electronic impedance spectroscopy (EIS) techniques. The percentage degradation was determined using a UV-visible spectrophotometer, while the mineralization of CR dye was further confirmed by chemical oxygen demand (COD) and kinetic analysis. The effect of operational parameters such as initial concentration of dye and pH on the degradation of CR dye has been studied to determine the optimum conditions. A possible degradation mechanism based on the electrospray ionization mass spectrometry (ESI-MS) has been suggested. The results demonstrated that CR dye was completely degraded in 5 h using the designed photocatalytic reactor. The electrical energy per order (E-Eo) was calculated for estimating the electrical energy efficiency. The result demonstrated that highly adhered nanotube array can effectively be used for photocatalytic degradation of CR dye in the presence of UV-LED light irradiation.