Study on Sonocatalytic Degradation of Tetracycline Hydrochloride by Mesoporous BiOI Microspherical Under Ultrasonic Irradiation

Abstract

Degradation of tetracycline hydrochloride (TCH) was carried out using natural light driven BiOI photocatalyst through sonophotocatalytic technique. Sonocatalytic degradation was considered as a new and advanced strategy for the elimination of hazardous organic pollutants from wastewater. Until now, the synergy of employing ultrasonic irradiation with BiOI based on catalysts for the removal of antibiotic residues is rarely reported. BiOI was an excellent semiconductor catalyst of Bi class. In this paper, mesoporous BiOI microspheres self-assembled from nanosheets were prepared by solvothermal method and its ultrasonic catalytic performance was studied. The sonocatalytic performance of BiOI was evaluated in terms of the degradation of tetracycline hydrochloride (TCH) as a simulate pollutant under ultrasonic irradiation. Three comparative experiments were designed to explore the degradation of TCH in natural light as follows: ultrasound alone, BiOI alone and ultrasound/BiOI synergy. The degradation rate of TCH by ultrasound/BiOI synergy was 227 times higher than that catalyzed by ultrasound alone and 83 times higher than that catalyzed by BiOI, and the maximum degradation ratio of TCH could reach to 93.0%. Therefore, the synergistic effect was significant, and the value of synergy factor was estimated as 61. Many factors, such as the ultrasonic power, catalyst concentration (Ccatalytic), ultrasonic duty cycle, concentration of initial TCH dye (CTCH), could affect the ultrasonic degradation efficiency. The BBD methodology with RSM was applied for modeling, optimization and investigation of influence of operational parameters, i.e. ultrasonic power, catalyst concentration, ultrasonic duty cycle. Analysis of variance (ANOVA) confirmed a good quadratic response surface model for predicting the sonocatalytic efficiency at various operational parameters (R2= 0.9936 and Adjusted R2=0.9854. The possible mechanism of the high degradation rate of TCH might be associated with the generation of reactive oxygen species (ROS) which could improve the chemistry yields.