Photoelectrocatalytic and Ultrasonic-Assisted Effects for Organic Dye Degradation Using Zinc Oxide (ZnO) Electrode

Abstract

The organic dye is one of the carcinogenic and toxic substrates that are used as the colorant in industries. Therefore, we have to develop the efficient technique to remove the dye in wastewater. This research aimed to develop the photoelectrocatalytic (PEC) cell with the high efficiency, which offered a simple method to remove dye from the wastewater. The ZnO photoanode electrode was considered for developing to enhance the efficiency of PEC cell for dye degradation. The ZnO electrode was fabricated by cyclic voltammetry method and then was compared the oxidation efficiency to ZnO electrode from dip coating. The film thickness of ZnO was controlled by the number of scan for a cyclic voltammetric method and the deposition time for the dip coating method. The effects of scan rate, the number of scan and calcination temperature were optimized to obtain the highest oxidation efficiency. Absorption properties, photoelectrocatalytic activity and electrochemical impedance spectroscopy (EIS) were measured to confirm the characteristic of the two fabricated electrodes. The results showed that ZnO electrode fabricated by cyclic voltammetry presented higher photoelectrocatalytic activity for water oxidation than that from dip coating. Thus, in this research was development ZnO electrode by cyclic voltammetry to degrade organic dye using the photoelectrocatalytic technique. The efficiency of dye degradation was evaluated by the decreasing absorption of methylene blue dye (5 mg/L) as a function of time. It was found that the photoelectrocatalytic dye degradation efficiency with ultrasonic-assisted was enhanced up to two times with 71% degradation in 1 hour. Therefore, we concluded that the developed ZnO electrode by cyclic voltammetry demonstrated a high photoelectrocatalytic performance with ultrasonic-assisted degradation of organic dyes.

Solar-Light-Responsive Nanomaterials for the Photoelectrocatalytic Degradation of Stubborn Pollutants

“…Therefore, most PEC degradation of organics use ZnO anodes and applied UV illumination for better degradation efficiency. For instance, ZnO photoanodes have been successfully used to degrade p-nitrophenol [55], methylene blue [56] and terephthalic acid [57] in aqueous solutions with UV irradiation. To facilitate PEC degradation using ZnO photoanodes with solar light, appropriate strategies are often employed to improve the visible light photocatalytic activity of ZnO.…”