Synthesis and stabilization of ZnO nanoparticles on a glass plate to study the removal efficiency of acid red 18 by hybrid advanced oxidation process (ultraviolet/ZnO/ultrasonic)

The aim of this study was to determine the amount of Acid Red 18 removal by the sonophotocatalyst process using ZnO nanoparticles. The ZnO nanoparticles were synthesized by the hydrothermal method and placed on a glass plate. The structure of the nanoparticles was investigated by XRD, TEM, BET, EDS, and SEM, and the effects of the processes involved in the sonophotocatalyst process (photolysis, adsorption, sonolysis, sonocatalysis, and photocatalysis) were compared. The highest removal rate was 94% at the initial concentration of Acid Red 18 (25 mg/L) in pH = 10 and catalyst concentration of 1.66 g/L during 45 min. The mineralization of AR 18 was confirmed by chemical oxygen demand and total organic carbon measurements. Acid Red 18 degradation by the sonophotocatalyst process followed the pseudo-first-order kinetics (R 2 = 0.97). The stability of the synthesized and stabilized ZnO nanoparticles was investigated during five cycles (investigation reusability) in this process, and it was found that these nanoparticles have high stability. Therefore, the sonophotocatalyst process as a hybrid advanced oxidation process with high efficiency in a short period of time is able to degrade and remove resistant organic pollutants from the environment and can be employed in industrial applications.