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

摘要

The organic dye is one of the carcinogenic and toxic substances that are used as the colorant in industries. Therefore, we have to develop an efficient technique to remove the dye in wastewater. This research aimed to develop the photoelectrocatalytic (PEC) cell with the high efficiency and a simple method to remove dye from the wastewater. The ZnO photoanode electrode has been developed to enhance the efficiency of PEC cell for dye degradation. In this study, the ZnO electrodes were fabricated by cyclic voltammetry method and were compared the oxidation efficiency to ZnO electrodes 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 the 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, the ZnO electrode by cyclic voltammetry was applied for degradation of organic dye using the photoelectrocatalytic technique. The efficiency of dye degradation was evaluated by methylene blue absorption (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 dye.