Study on the development of an innovative type-II sonocatalyst of BiVO4/FeVO4 and its application in sonocatalytic removal of tetracycline

BiVO₄ demonstrated immense potential as a photocatalyst, featuring excellent responsiveness to visible light, non-toxic properties, and a low band gap. Nevertheless, the electron-hole pair recombination rate of BiVO₄ hindered its widespread practical utilization. To overcome this challenge, this research focused on synthesizing BiVO₄/FeVO₄ heterostructure nanocomposite materials aiming to facilitate the effective segregation of electron-hole pairs and unlock its full potential capabilities in sonocatalytic area. In the present study, BiVO₄/FeVO₄ heterostructured nanocomposites were successfully synthesized by the hydrothermal synthesis method, and morphology, structure, physics, chemistry and characteristics of the prepared sonocatalysts by various technical means. It was confirmed that FeVO₄ with a rod-like structure was attached to BiVO₄ with a plate-like structure. The sonocatalysis activity of BiVO₄/FeVO₄ composites was investigated by analyzing the removal process of the drug model tetracycline(TETR). Under the experimental conditions when the added amount of FB-60 sonocatalyst was 1.25 mg/mL, the added amount of K₂S₂O₈ was 3 mg/mL, the initial concentration of TETR solution was 50 mg/L, the initial pH of TETR solution was 6, the ultrasound power was 500 W, the ultrasound frequency was 50 kHz, and the ultrasound time was 30 min, the removal rate of TETR by FB-60 sonocatalyst reached 94.8 % ± 1.09 %. Compared to bare BiVO₄, the FB-60 heterojunction exhibited significantly enhanced sonocatalytic activity in degrading TETR. The increased activity could be linked to the formation of type-II heterojunctions, which promoted the effective separation of electron-hole pairs. In addition, after four rounds of cycling, the removal rate of TETR remained at 90.66 ± 0.98 %, demonstrating its excellent stability of sonocatalytic performance. The results showed that FB-60 heterojunction, a new type of sonocatalyst, could be utilized for wastewater treatment.